m.f.u.t.u., phr. — Green’s Dictionary of Slang

m.f.u.t.u. phr.

[abbr., orig. WWII milit., inscribed on B-17 bombers with a cartoon of General Hideki Tojo (1885–1948) getting ‘the finger’]

(US) a term of abuse, motherfuck you too.

1942

in W.N. Hess B-17 Flying Fortress 32: [photo of Pacific B-17 plane nose art] MFUTU.