a dishonest, knavish person; scoundrel.
a playfully mischievous person; scamp: The youngest boys are little rogues.
a tramp or vagabond.
a rogue elephant or other animal of similar disposition.
Biology . a usually inferior organism, especially a plant, varying markedly from the normal.
I assume 4 and 5 don't apply here for obvious reasons, and neither does 3 because, although debatable, I like to think Valeera is more classy than that. Same for number 1, as Rogue is a class for gentlemen and scholars, who are by no means any sort of scoundrels.
So that leaves us with number 3, a playfully mischievous person. The "playfully" adverb describes the nature of cards games pretty well, so we don't need to discuss it either. Now let's see the "mischievous" adjective. The Rogue class makes use of stealth mechanics and surprise attacks like Leeroy plays to win, rarely taking on the opponent head to head because Rogue minions will take a beating from pretty much any other class's minions (ex: Ancient of War is huge, so if it slapped your girlfriend's a** in a bar would you punch him? Hell no, the dude's 5 times your size, you'd have to be crazy. Instead, you Sap him and shank the hell out of that wimpy Druid hiding behind him).
Is this enough to decide if Valeera is a Rogue? Probably, but at least we can all agree she's rouge, because she clearly likes to wear red.