Added 9 October 2026 loco /ˈləʊ.kəʊ/ adjective Categories: Describing WordsRare Words adjective ! Definition from WordNet 3.1, Princeton University. Pronunciation from Wiktionary, via Kaikki.org. More about loco at Wordnik → Where our words come from → Informal or slang terms for mentally irregular. it used to drive my husband balmy Origin Borrowed from Italian. From Wiktionary, via Kaikki.org (CC BY-SA) Related Words: loopycrackerswackycrackedkookybattyinsanebatsloonybonkersdottybarmy Back to today's word