The Lights Are On But Nobody’s Home

Also: The lights are on but no-one’s home.

Meaning of Idiom ‘The Lights Are On But Nobody’s Home’

The lights are on but nobody’s home is an expression used to describe someone who is not very intelligent or who is considered stupid; it is also used in when someone does not react when spoken to, perhaps because they are focused on a task or are thinking about something else. 1McCarthy, Michael. Cambridge International Dictionary of Idioms. Cambridge University Press, 2002

Examples Of Use

“What is going on with John today? It’s like the lights are on but nobody’s home.”

“That guy who just moved into the apartment next door is strange. The lights are on but no-one’s home.”

“Once Dennis starts playing video games there is no use in talking to him. The lights are on but nobody’s home.”

“I’m not going out with Tracy again. She is very sweet and pretty but so dumb. The lights are on but nobody’s home.”

The lights are on but nobody's home idiom meaning

Origin

Used since at least the late 1980s.

When all the lights are on inside a house, we expect that house to be occupied. It is unusual for a house to be fully-lit when its occupants are out. This expression uses such an occurrence to describe a person who seems fully functional and animated but who is ‘vacant,’ or, in other words, unintelligent or unaware.


More Idioms Starting with L

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Sources   [ + ]

1. McCarthy, Michael. Cambridge International Dictionary of Idioms. Cambridge University Press, 2002