The general answer is, both. Riot's definition of Honor is both being sportsmanlike in general, and keeping your composure even in bad games - though, that's part and parcel with sportsmanlike behavior.
The Summoner's Code is a pretty decent example of what Riot expects out of their players. I'd personally like to highlight 4/6 of the Summoner's Code as most noteworthy;
Play as a team, win as a team!
A coordinated team is extremely difficult to take down. No matter how hard you feel like you’re carrying individually, blaming others and refusing to co-operate with teammates gives your opponent an advantage.
Don't rage, blame, or tear people down.
We’ve all had tough games where we fell behind, got camped super hard or missed an easy smite, only to get flamed in chat. Avoid making others feel that same way and report the ones who do.
Never feed intentionally and don't give up the fight!
Seeking revenge on your own team by intentionally feeding and helping the opposing team does not promote fair play. Keep a cool head if you fall behind, don't give up and always do your best.
Lead the way for newbies, be helpful.
Never forget the excitement you felt when you first set foot on the Rift. Don't mock newbies who are still learning the ropes or urge them to give up on League. Instead offer a hand when they stumble.