One of our AI overlords, ChatGPT wrote
Both "grump" and "grouch" refer to someone in a bad mood, but there's a slight difference in connotation:
- Grump: Refers to someone who is temporarily in a bad mood, often short-tempered or irritable. It's often associated with momentary feelings of annoyance, and the person is not necessarily negative all the time.
- Grouch: Refers to someone who is habitually or characteristically bad-tempered or surly. A grouch is more consistently cranky or difficult to deal with over time.
So, a grump might just be having a bad day, while a grouch tends to have a more permanent grumpy personality.