寡 is a bound morpheme (b.f.) used in formal or written Chinese, appearing in compounds with three main meaning areas: (1) 'few, scarce' (寡言, 寡不敌众), (2) 'tasteless, insipid' (寡淡, 清汤寡水), and (3) 'widowed' (寡妇). It cannot stand alone as an independent word; you must use it within these fixed or semi-fixed expressions. The 'widowed' sense is mostly used for women (寡妇) and only rarely for men (鳏夫). The 'few' sense can overlap with 少 but carries a more literary tone.