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Acronym: Head Down Mother Fucker! Typically used to indicate that either oneself or the recipient should put their head down and do some work.
Worker1: So worker2 how was your weekend?
Worker2: Good thanks. You?
Worker1: Oh fine. Hows the kids?
Worker2: Yeah pretty go-
Boss: Head Down Mother Fucker!
by thehelix August 16, 2010