Here's some things I consider god-modding.
1.) Players who use other characters or other characters' background to define theirs.
"No way any other character could defeat Badassatron, he is a Civire Kameiras with the most bleeding edge cybernetics and gene modification in EVE that no one else could ever get. Dont worry, hes not Mary Sue or anything, he had dyslexia. Yanno, so he's realistic"
or
Dominatrixia, after she escaped from sexual slavery in the Amarr Slave Brothel on Misery IV, became the highest scoring pilot to come out of the Republic Military Academy ever. She still has a statue there. Your character probably saw it when she studied there.
2.) Players who ignore PF to suit "the way its always been" when it comes to describing the world.
"Look, I dont care about what Evelopedia, those two chronicles, the Burning Life, and common sense says about my faction, we've always played it this way, and really, all that stuff is stupid. Dont be so Tony G."
3.) Players who tell you what you can and cant react to as another player.
"Look, bro, when he was out roaming around and shooting people in your low sec with a bunch of red-flashy outlaws, that was totally, like, out of character and really just fun time. IC he was back home supporting his faction. Hes not really a pirate or anything."
Basically, I think of godmodding as any player who unilaterally seeks to control the game world or other people's characters to suit their own proclivities.