wife (vulg), (kokuji)
嬶 is a Japanese-coined character (kokuji) that refers specifically to a wife in a vulgar or colloquial sense. Its meaning is narrow and does not extend to other family roles.
嬶 is a kokuji (Japanese-created kanji) formed by combining 女 (woman) with 鼻 (nose), likely as a pejorative or colloquial reference to a wife. The exact historical motivation is uncertain.
A woman (女) with a prominent nose (鼻) is a crude way to picture a wife in this vulgar kokuji.
For かか, imagine a wife cackling loudly: cackle -> かか, and her nose (鼻) is right there in the character.
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wife; the missus