To complain or grumble in an annoying, whining manner, often used in British English.
British dialect origin, possibly from Old English 'witan' (to know or blame). The '-er' suffix creates a diminutive or continuous action sense, evolving into meaning petulant complaining.
Witter is wonderfully British—it's the perfect word for that specific type of complaint that's constant but low-level, like background noise. Americans struggle to explain it because they'd need four words where British English has this one gem.
Complete word intelligence in one call. Free tier — 50 lookups/day.