noun
single man; bachelor
Refers to an unmarried man, often with a nuance of being available or living alone. Common in everyday conversation and writing.
彼はまだ独身男だ。
He is still a single man.
独身男の生活は気楽だ。
Life as a bachelor is carefree.
The female counterpart, meaning 'single woman' or 'spinster' (though the latter can carry a dated nuance).
Compound of 独身 (どくしん, 'unmarried') and 男 (おとこ, 'man'). The exact historical derivation is straightforward; the word is a transparent modern compound.