1. most crazy or silly in a harmless or amusing way
Usage: informal; superlative form of loony

Examples

• That was the looniest idea I’ve ever heard.
• She came up with the looniest excuse for being late.
• The looniest character in the movie made everyone laugh.
• His looniest invention actually worked perfectly.
• Of all her crazy schemes, this is the looniest one yet.
• The looniest part of the story was completely true.