say it: in-SAYN
insane is an adjective meaning "afflicted with or characteristic of mental derangement". It carries 2 recorded senses.
afflicted with or characteristic of mental derangement
“was declared insane”
“insane laughter”
very foolish
“harebrained ideas”
“took insane risks behind the wheel”
“a completely mad scheme to build a bridge between two mountains”
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for insane come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.