1 (humorous) a person who behaves badly, but in a harmless way syn scoundrel: He's a bit of a rogue, but very charming.
2 (old-fashioned) a man who is dishonest and immoral syn rascal: a rogues' gallery (= a collection of pictures of criminals)

Definition in the CALD:

1 OLD-FASHIONED HUMOROUS a person who behaves badly but who you still like:
"Come here, you little rogue!" chuckled my uncle.
The women all think he's a loveable old rogue.
2 OLD-FASHIONED a dishonest or immoral man

Firstly, I agree with the CALD that 'rogue' is fairly old-fashioned in both senses (I suspect some may disagree).
Secondly, I prefer the CALD's definition for meaning 1 as a 'loveable rogue' may well find their actions to be harmful even if it wasn't their intention (OALD - 'behaves badly but in a harmless way'). For any sci-fi fans, a classic example of a loveable rogue would be Han Solo from Star Wars.
Would 'brètol' cover meaning 2 rather than meaning 1? I ask because, if this is the case, I think we need to also add an equivalent for meaning 1.

As to 'rogue state', we would need to add this to an adjectival entry.

OALD:
1 (of an animal) living apart from the main group, and possibly dangerous
2 behaving in a different way from other similar people or things, often causing damage: a rogue gene * a rogue police officer

CALD:
1. behaving in ways that are not expected or not normal, often in a destructive way:
a rogue state, rogue cells
2 [before noun] SPECIALIZED A rogue animal is a fierce, dangerous animal that lives apart from the rest of its group

Personally, I do not think we need to add meaning 1 from the OALD (meaning 2 in the CALD). As the CALD suggests, this usage is somewhat specialized. What, however, might we put for the meaning 'behaving in a different way from other similar people or things, often causing damage'? In the case of a rogue person (rogue policeman, scientist etc.) perhaps 'inconformista' or 'dissident' (though the sense of 'often causing damage' is missing)? As to 'rogue genes or cells'? Any ideas???

He donat una ullada als sinònims de brètol: belitre, bandarra, galifardeu, bergant, bergantell, brivall, canalla. La majoria són passats de moda i tots poden usar-se en sentit humorístic. En català hi ha la tendència a fer servir aquestes paraules per a referir-se als adolescents o als xiquets, i moltes han acabat convertint-se en sinònims de noi o adolescent: galifardeu, bergant, bergantell, brivall, canalla (conjunt de nens).

En el diccionari podríem posar aquests sinònims que cobreixen els dos significats:

rogue adj
bergant, brètol, brivall, belitre.