SAT GRE lunacy Definition Lunacy refers to insanity or extremely foolish behavior. Example "Driving at that speed in the city is pure lunacy." Sign in to save SAT Quiz → GRE Quiz → ← lump lunar → Study tips featuring "lunacy" Map the Author's Attitude Before Reading Questions Force Contrast Between Two Similar Words Stop Skipping Words and Read the Tone Related words SAT antonym SAT abase SAT abdicate SAT abdomen SAT abduction SAT abet SAT abeyance SAT abject SAT abjure SAT ablution SAT abnegate SAT abnormal