adj, noun, slang ·Common ·High school level

Definitions

Noun

1. 1
   An insane or very foolish person. derogatory, informal, offensive

   "Why, there’s hundreds of lunies of the sort to be met in London."

2. 2
   someone deranged and possibly dangerous wordnet

Adjective

1. 1
   Insane. derogatory, informal, offensive

   "loony scheme"

2. 2
   Very silly, absurd. derogatory, informal, offensive

Adjective

1. 1
   informal or slang terms for mentally irregular wordnet

Synonyms

All synonyms

crazyabsurdapisharound bendaround the bendasinine

Antonyms

All antonyms

subtle

Example

More examples

"Some people might regard belief in ghosts as loony."

Etymology

Shortened from lunatic, and likely also from loon ("rascal", and also the bird) + -y.

Related phrases

loony binloony dookerloony leftloony leftyloony toonloony tuneloony tunesloony van

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.