noun
Dated, familiar term for one's own wife. Used mainly by men in casual or old-fashioned speech. Not used to refer to someone else's wife.
うちの細君がうるさくてね。
My wife is a nag, you know.
細君に相談してみるよ。
I'll talk it over with my wife.
noun
wife (of a peer or subordinate)
Dated, somewhat condescending term for the wife of a peer or subordinate. Rarely used in modern Japanese; 奥さん or 夫人 are more common.
同僚の細君もその集まりに来ていた。
My colleague's wife also came to the gathering.
The kanji 細 (small, detailed) and 君 (lord, you) combine to form a term that originally referred to a wife in a humble or familiar manner. The exact historical derivation is uncertain.