Manly doesn't cover it though. Manly is just that. Manly.. it lacks the ideals of courage, of self-sacrifice and the guts to do what you know needs to be done, regardless of how shit will end up for you. That is what GAR is.
Kenpachi's MANLY, but he isn't GAR, for example. Hiraga Saito of ZnT is GAR because of him fighting the 70,000 Albion soldiers, sacrificing himself. Archer is GAR because he fought with Berserker just to buy time, even if he knew he wouldn't be able to win, and went out with style.
Fuck me, because this will cause a huge sagefest, but Kamina was GAR because he didn't give a shit if he was dying, he still had the guts to get up, give Simon a punch to the face, a mouthing off and then obliterated the enemy leader.
There are other characters possessing this kind of heroism, or the willingness to act in the same manner, but many people mistake common concepts of them with being GAR. Manly isn't GAR. Knowing lolhax skills isn't GAR. It's knowing you're probably going to die doing this, but deciding 'fuck it, I'll do it because this is what I want to use my life for'.