What is S.e.m.f.?
1.
"Speak English, Motherfucker"
Acronym that should frequently and forcefully offered to immigrants--legal or illegal--to the US who refuse to assimilate and insist on jabbering in foreign tongue.
As I was getting on the 2 train in Wakefield, I passed a gaggle of babblers spewing forth "espanol." "S.E.M.F.!" I said. They thought it had something to do with green cards and the INS, and they scattered like cockroaches in the light.
See 
2.
Shit Eating Mother Fucker
A little boy just stole your candy.
you yell, "Come back here you little semf!"
Random Words:
1. 
a person who is attracted to someone of the same sex
School is reeeeal unheterosexual
See homosexual, gay, fag, gaylord, flamer
2. 
s..