noun
cheating man; flirt
A man who is unfaithful in a relationship or habitually flirts with others. Often carries a negative, judgmental tone.
See also: 浮気
彼は浮気男だから、信用できない。
He's a cheater, so I can't trust him.
あの浮気男はいつも他の女性にちょっかいを出している。
That flirt is always hitting on other women.
The female counterpart, meaning a cheating woman or a woman who flirts.
Compound of 浮気 (うわき, 'cheating, affair') and 男 (おとこ, 'man'). The exact historical derivation of 浮気 is uncertain, but the compound straightforwardly means 'cheating man'.