(same universe as "The Life and Times," my WIP, and though reading that might help one enjoy this a bit more, it's not a prerequisite).
A nickname—a good nickname—says a lot about the person it is assigned to, but it also says a lot about the person assigning it.
Moony, Wormtail, Padfoot, and Prongs are monikers delineating the alternate forms of the four Marauders—Animagus forms for the last three, and for Remus, his unwilling alter-ego as a werewolf. And how, exactly, can you get more personal than the animal representation of your being? But the really, truly telling part about "Moony," "Wormtail," "Padfoot," and "Prongs" is that the four wizards choose to identify themselves by these potentially revealing nicknames. They choose to use the names that explicate their deepest (and in Remus's case, darkest) secret. It is a bit risky, really, but that is what makes the nicknames so fitting—Marauders take risks.
Over the years, there are a lot of nicknames.
Almost the instant he begins to notice girls, Sirius Black comes up with "Teeglow"—T.G.L.O.: "The Good-Looking One"—for the fittest girl in their year, Carlotta Meloni.
James Potter arrives at "Flatface" for Roger Diggory, after he notices the Ravenclaw possessing remarkably level features chatting with Lily Evans before their Potions final fourth year.
Adam McKinnon—the only non-Marauder resident of their dormitory—is "Number Five."
Severus Snape is "Snivellus" (the first nickname). This is particularly apt, as far as James and Sirius are concerned, because it not only accurately describes the git, but it sums up their opinion of him rather well.
Mundungus Fletcher is "Dung."
Donna Shacklebolt is "Shack."
Patricia Sorbetski is "Strawberry" ("As in Tart," Sirius always faithfully adds.)
However, for the longest time, James doesn't call Lily anything but "Evans."
And it's funny, because almost the first time they meet, it occurs to him that there are a great many nickname possibilities for this girl with the bright red hair and gigantic green eyes. Plus, each and every nickname has the potential of absolutely infuriating Lily, and that is an opportunity that James rarely passes up.
The truth, though, is that no casually cast handle describes Lily quite right. None of them capture Lily Evans, and none of them taste quite right rolling off James' tongue—not the way "Evans" does.
(It's a little frustrating, actually, but then again, everything about Lily Evans is at least a little frustrating.)
They meet first on the Hogwarts Express. She enters and exits the compartment with Snivellus, and only a few, scathing words are exchanged. They are just eleven, and Sirius doesn't give the meeting a second thought, except perhaps where it pertains to his own House situation. James gives the meeting quite a few second thoughts, though, and he doesn't know why, but he can't help glancing after her as she hurries away with Snape, and he can't help trying to chat with her later in the afternoon, and he can't help feeling just a bit let down that she doesn't seem to want to have anything to do with him. Sirius may not give the meeting much of a second thought, but James gives it about two dozen second thoughts over the next few months.
But he doesn't say as much, because they are just eleven, and he does not quite know what to do with the strange panging in his chest that takes effect whenever Lily sends him a withering glare; whenever she is thoroughly unimpressed by the antics that do not fail to garner everyone else's admiration; eventually, whenever she rejects one of his falsely careless Hogsmeade invitations.
He tries a few nicknames throughout fifth year, at the height of Lily's loathing for him.
"Oi, Legs!" earns him a death threat. "Ginger," has her rolling her (fantastically) green eyes, as if to sarcastically say, "Very original."
He calls her "Saint Charity," for hanging around with Snape, and she smacks him.
So, most of the time, she's just "Evans..." or "L.E." scribbled across parchment after his Defense O.W.L. She doesn't know about that, though, and he's glad of it.
(He doesn't want to change for her. He doesn't want to be pathetic and try to be whatever it is that he secretly thinks that she secretly wishes he were. He wants to forget what she says after she says it, rather than have her voice linger in his brain indefinitely. He wants to feel nothing when she smiles and to possess a scroll of Transfiguration notes that doesn't have those stupid initials doodled in the corner).
At the beginning of sixth year, there's a fight, and it's all James's fault. He punches Nicolai Mulciber, and one thing leads to another, and later, he's squabbling with Evans about it.
"You can't just sit around and let people say whatever the hell they want, Evans."
"Actually, that's exactly what you can do, Potter! Haven't you ever heard of 'sticks and stones?'"
"It's called standing up for the right thing, Evans!"
"But you have to pick your battles!"
Maybe she's right. Maybe he shouldn't have punched Mulciber, even though the git inevitably had it coming. Maybe he should have let Evans sort out the little spat in her own, less violent way.
Still, he's not about to back down and tell her the truth.
The truth is that he saw Mulciber fighting with Lily, and something inside of him just snapped.
It's what always happens: he doesn't mean to always say the wrong thing to her, to make her hate him, to feel intensely bitter towards her prat boyfriend, to punch blokes that speak unkindly to her. It just happens: the part of his brain that is logical and reasoning snaps when it comes to Lily Evans.
It's about a week later that he finds her in the library, talking to herself as she plods through homework, and his heartstrings don't just tug, but altogether snap at the sight of her.
They're bantering twelve seconds later, but not in a friendly way—he's glad she's speaking to him at all the way he's behaved, but she's just vexed. At some point, a nickname pops into his brain, and it's as he's leaving that he uses it.
"Relax, Snaps, it's not as though..." He finishes with some jab at her, and she rolls her eyes, a sarcastic remark rising to her lips, until she seems to realize that he's called her something foreign, and she breaks off mid-sentence, with:
"...What did you call me?"
He only grins and adds: "See you around, Snaps," before he departs.
James can feel her scowling after him.
He continues to call her "Snaps," for about a week. It annoys her, because she can't seem to figure it out, and every time she breathes a deep, calming breath, or tries to look as though she doesn't care, he can tell that her irritation with him is growing. He wants her to ask what the nickname means, and he knows she knows he wants her to ask. She doesn't break though—not really.
On Friday, she tries to get it out of Sirius, but even Sirius doesn't have a clue what it's about—why after five steady years of "Evans," she's finally got a proper nickname—and he doesn't really inquire. For Sirius, it's just another of James's Lily Things that he has come to accept (and ignore) over the years.
Saturday night, they're arguing in the Common Room again.
"The extent of your self-righteousness never fails to amaze and bewilder me, Snaps."
"The ABCs never fail to amaze and bewilder you."
"Oh, I'm sorry... what did you get on your O.W.L.s again? Was it... seven O's? Wait. No. That was me."
"My Merlin, really? I don't think you told anyone yet... except for once every ten minutes since you stepped onto the platform!"
"At least I have something to brag about."
Lily exhales heavily, bored and worn out. "This is stupid. I'm not doing this anymore. I'm not fighting with you. I'm not talking with you. I'm ignoring you. Everyone will be so much better off if we just don't interact."
"Fine with me, Snaps," he lies, and the fun of annoying her (getting her attention) has gone.
She turns to storm away with all appropriate drama, and he hopes she doesn't mean it. Fortunately, the witch pauses before she reaches the staircase up to the dorms. She halts for a full five seconds, and then turns back to face James.
"Gingersnaps," she says.
James isn't quite sure what she's talking about. He stares back at her, blinking and confused.
"Gingersnaps..." she repeats. "Ginger-biscuits... the desert." She points to her hair. "Ginger. Snaps."
It's another moment before James realizes that she thinks she's figured out the nickname.
"Clever," she says.
It would be, he supposes.
But he can't possibly explain what it's all about really. He can't explain about hitting Mulciber or the fact that he only ever says incoherently stupid things to her, or that he doodles her name on parchment like a love struck twelve-year-old witch. And so he grins.
"I should have known it involved food," she remarks, and her hair swishes and shines when she turns to retreat up the stairs to the dormitory.
Her voice echoes like a song stuck in his head, and his chest gives a pang and a snap.
So he decides not to correct her.
Because this particular nickname might say a little too much about the person assigning it.