lunatic

Everyday

1. (informal) A person who behaves in a wild, silly or dangerous way: «He drives like a lunatic». tree →
2. (adjective, informal) Very silly or crazy: «a lunatic idea». tree →
3. (old, now offensive) An old word for a person with a serious mental illness; today it is hurtful to use it this way. tree →

In the lessons

In everyday speech people say «drives like a lunatic» or «a lunatic idea» to mean reckless or crazy. In history lessons you meet «lunatic asylum», an old name for a hospital for people with mental illness. Today we say «mental illness» and «psychiatric hospital» instead, because «lunatic» about real ill people is hurtful. The word comes from Latin «luna» (moon): people once wrongly believed the moon made people mad.

Examples

• Some lunatic was driving at 80 miles an hour past the school! tree →
• Jumping off the shed roof was a lunatic idea. tree →
• The crowd went lunatic when the goal went in. tree →
• In Victorian times there were places called lunatic asylums. tree →
• Grandma says the price of petrol is lunatic. tree →
• He was running round the garden like a lunatic. tree →
• Today we say «a person with a mental illness», not «a lunatic». tree →
• Some people believed a full moon made people act like lunatics, but science has not shown this. tree →

Note

Countable: one lunatic, two lunatics. Informal and a bit rude when said about a person; never use it about people who are really ill. Myth: the full moon does not make people mad – studies have not found this. Related: «lunar» (about the moon), «lunacy» (madness, foolishness). Not a maths word.