1. superlative form of insane; most insane; extremely mad, mentally ill, or irrational
Usage: informal: often used colloquially to mean extremely foolish or reckless

Examples

• That was the insanest decision he could have made.
• The insanest part of the movie was the final plot twist.
• She came up with the insanest idea for the party.
• The insanest weather we've ever experienced happened last winter.
• His insanest stunt involved jumping off a building into a pool.