It's another way of saying "for God's sake" but usually used if your pissed or frustrated about something.
Chris: Where's Rich?
Marcus: He's still inside.
Chris: For fuck sakes! Call him out, we're already late.
sake! English or Irish derived.
Usually used in a soccer game to express anger or hurt.
For fuck sake, what's wrong with you?
Fuck sake, that hurt!
Mistaken spelling of the phrase 'for fuck's sake', meaning 'for the sake of fuck' derived from 'for god's sake' (for the sake of god)
"I've lost all your money on the dog races"
"fuck sakes!" (incorrect)
"for fuck's sake!" (correct)
an exclaimation of disgust and disappointment regarding something
for fuck sakes! i´ve told you a 1000 times to leave the bloody thíng alone - now it´s fucked...
annoyed and in a small space
Getting really pissed off in a life there would be enough room to say "for fucks sake" so you'd have to say FUCKSAKE