A term oft-used by teenage and/or pre-pubescent boys that play Call of Duty: Black Ops at least 4 hours every day. The term is often yelled into a headset while playing on Xbox Live so as to alarm and thus disturb the gameplay of other players.
Emphasis is usually put on the "e" and "o" in Leroy, dragging out the pronounciation. i.e. Leeeeerooooy. While emphasis is put on the second syllable, "kins" in Jenkins. i.e. JenKIIINS.
"Dude! WTF I just got killed because you distracted me.