MF'er

Mute Forever. Used in elite criminal organizations to show that the wearer is never going to talk about anything with someone outside their organization.

Tiny,"Hey Bob I think that Tom snitched on us."
Bob," Naw Tom is a stand up MF'er"

by ERICWRIGHT075 April 23, 2021

Mf'er

Short for mother fucker. Can also be said as mf.

Boy one: HEY! THAT MF'ER TOOK MY MINECRAFT
Boy two: Just let it go dude

by A_Bi_Legend November 11, 2020

mf'er

Military abbreviation for "My Friend."

Sgt. Connelly was one courageous MF'er.

by zabazuve-ha September 19, 2007