f.y.f.i., phr. — Green’s Dictionary of Slang

f.y.f.i. phr.

[abbr.]

for your fucking information, acronym often appended to memos in business.

1995

cited in J. Sheidlower F-Word (2nd edn) [online t/s] FYFI means “for your fucking information.” I’ve seen it used on memos for at least ten years—everyone knows what it means.