C2nouninformal10K+

Lunatic

UK //ˈluː.nə.tɪk//US //ˈluː.nə.tɪk//

Definition

A person who is considered insane or wildly irrational.

In simple words: A person who is crazy or behaves very strangely.

Examples

  • The scientist was called a lunatic for his bizarre theories.
  • He acted like a lunatic when he found out he won the lottery.
  • Some people believe that the full moon drives lunatics to behave strangely.
  • You can't call someone a lunatic just because they have different opinions.
  • Her friend warned her, 'Don't let that lunatic near your car!'

Usage notes

Often used in a derogatory way to describe someone perceived as irrational or mentally unstable. Be cautious of context; using 'lunatic' may offend some.

Grammar pattern

standalone noun

Memory hint

Think of a 'moon' that makes people act crazy. 'Luna' means 'moon' in Latin.

Collocations

  • crazy lunatic
  • dangerous lunatic
  • mad lunatic

Synonyms

  • crazy person
  • madman
  • insane person
  • fool
  • maniac

Antonyms

  • sane
  • rational
  • reasonable

Common mistakes

  • Using 'lunatic' to describe someone without mental illness.
  • Confusing with 'maniac', which has a slightly different meaning.
  • Overusing in serious contexts where a more respectful term is appropriate.