姑子

gūzi
  1. husband's sister
  2. (coll.) Buddhist nun

CEDICT

colloquial

Entry Composition

1 姑 gū
  1. paternal aunt
  2. husband's sister
  3. husband's mother (old)
  4. nun
  5. for the time being (literary)
2 子 zi noun suffix, as in 椅子 yǐzi "chair"