noun
A man whose wife has died and who has not remarried. The term is somewhat formal or literary; in everyday conversation, 男やもめ is more common.
彼は若くして寡男になった。
He became a widower at a young age.
寡男として子供を育てるのは大変だ。
It's tough raising children as a widower.
The reading やもお is of uncertain origin. The kanji 寡 and 鰥 both carry the meaning of 'widower' and are used as semantic spellings.