noun
mature woman; middle-aged woman
Refers to a woman past her youth, typically in her 30s or older. Can carry a slightly dated or colloquial tone; in modern usage, it may be considered impolite or old-fashioned depending on context.
彼女はもう年増だが、まだとてもきれいだ。
She is already a mature woman, but she is still very beautiful.
年増の女性が一人で旅行するのは珍しくない。
It's not unusual for a middle-aged woman to travel alone.
熟女 is a more modern and sometimes euphemistic term for a mature woman, often with a positive or sensual nuance, while 年増 is more neutral and traditional.
おばさん is a common, informal term for a middle-aged woman, but can be considered rude if used directly; 年増 is less personal and more descriptive.
年 (toshi, 'year, age') + 増 (ma, 'increase'). Literally 'increased years', referring to a woman who has accumulated years.