Monster-in-law
noun, slang
noun, slang ·Uncommon ·Advanced level
Definitions
Noun
- 1 A very unpleasant mother-in-law (spouse's mother). colloquial, humorous
"So when we belatedly celebrated Caspar's third anniversary the following weekend, I was notably frosty towards her. But this is not a typical tale of monster-in-law woes."
Example
More examples"So when we belatedly celebrated Caspar's third anniversary the following weekend, I was notably frosty towards her. But this is not a typical tale of monster-in-law woes."
Etymology
Blend of monster + mother-in-law.
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Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.