Informal a relative by marriage
Origin of in-law; from mother- (or father-, and the like ) in-law
being a (specified type of relative) by marriage, not by descent in the same family line
A relative by marriage.
Origin of in-lawBack-formation from such compounds as mother-in-law.
- Alternative spelling of in-law.
(third-person singular simple present inlaws, present participle inlawing, simple past and past participle inlawed)