insane insane /ˌɪnˈseɪn/

adjective

1. () Afflicted with or characteristic of mental derangement  ( insane )
   afflicted with or characteristic of mental derangement
    Was declared insane
   was declared insane
    Insane laughter
   insane laughter
   
2. () Very foolish  ( harebrained , mad , insane )
   very foolish
    Harebrained ideas
   harebrained ideas
    Took insane risks behind the wheel
   took insane risks behind the wheel
    A completely mad scheme to build a bridge between two mountains
   a completely mad scheme to build a bridge between two mountains