also: ださお
noun
uncool guy; dork; nerd
Slang term for a man who is unfashionable, socially awkward, or unstylish. Often used teasingly or self-deprecatingly.
See also: ださい
あのダサ男、まだガラケー使ってるよ。
That dork is still using a flip phone.
俺ってダサ男だから、おしゃれな服が似合わないんだよね。
I'm such an uncool guy, trendy clothes just don't suit me.
Compound of ダサ (from ださい 'uncool') and 男 (おとこ/お 'man'). The reading お for 男 is a common suffix in male nicknames.