origin: a long time ago (a couple years back), the most famous wow player leeroy jenkins went with a raid with a couple other people. he was away from his keyboard and was missing out on the battle plan. while they were discussing it leeroy jumped on his computer and said "lets do this" and yelled out "LEEEERRROOOOOY JEENNNNKIINNS" everyone was shocked when he ran through. in short he got his whole team killed.
1.to do something rash and extremely stupid usualy in a group.
2. to do something rash but brave.
1. that idiot went and got his whole team killed, i wish he hadn't leeroy'd it.
2. don't even think about leeroying this one!
3. i think i'm going to leeroy this and save the day.