Loco

Part of speech: adjective, noun

Pronunciation: /ˈləʊ.kəʊ/

Definitions

1. Describing a state of mind marked by extreme irrationality or wildness while also referring to conditions in animals caused by toxic plants that impact the nervous system
2. Characterized by a manic or irrational mindset that signifies instability while also indicating pathological effects on animals resulting from toxic flora affecting their neurological functions
3. Showing wild or irrational behavior in people ; referring to animals suffering from a nerve-damaging condition caused by certain poisonous plants

Etymology: Spanish "loco" meant "insane, crazy, loose," and English borrowed the adjective in the sense of wild or irrational behaviour. The noun sense, the plant-poisoning meaning, came from the same Spanish word applied to the locoweed plants of the American West, which were thought to drive grazing animals out of their minds. Animals that ate them developed tremors, staggering and erratic behaviour, which gave the name to the condition. The Italian and Spanish source is the more distant link. Italian "loco," meaning "place," is a different word from the one in English "locomotive," which is a clipping of a longer form and is drawn from Latin "locus," meaning "place." That pairing explains a notable coincidence: "loco" appears in English both as a shortening of "locomotive" and "locofoco," and in the Spanish-derived sense of madness, two unrelated lineages that happen to share a spelling.

Synonyms: crazy, insane, wild, mad, nuts

Antonyms: sane, rational, calm, composed, stable