Meanings
nounmother-out-law (plural mothers-out-law)
plural mothers-out-law
- The mother of one's boyfriend or girlfriend.
- The mother of one's ex-spouse.
The old Cape Cod commune-istas had caught up enough with my mother out-law and were now asking after notable events in the lives of her offspring.
2006, Harlyn Aizley, Confessions of the Other Mother: Nonbiological Lesbian Moms Tell All! (Social Science), →ISBN, pZgDAQAAQBAJ, page 36
Origin
From mother + -out-law, by analogy to mother-in-law.
Full word history & related roots →Cite this entry
APA
mother-out-law. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/mother-out-law
MLA
“mother-out-law.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/mother-out-law. Accessed November 5, 2026.
Chicago
WatkinsX Dictionary, s.v. “mother-out-law,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/mother-out-law.
Source: mother-out-law on Wiktionary, CC BY-SA 4.0.