a person who does not inform their respective group of friends of a new relationship they are in.
Tyler, you're the motherfucker, why didn't you tell us about you and Ashley.
by whtsrl January 11, 2010
a person who is highly effective in accomplishing tasks, assignments, doing the bosses dirty work, etc. plain and simple the motherfucker is The person who gets things done !
having completed a sensitive task the manager said to Jeffrey, "Jeffrey you are The Mother fucker!"
by Zloyobar August 24, 2008