Phrase of the day

Discover a new phrase each day to use in your English! These are special phrases and sayings that English speakers use all the time, but you don't often see these phrases in English course books or other study material. Visit daily to learn some popular English phrases on a regular basis.
7th September 2025

On the brain

We use this expression to say that someone is obsessed with something or always thinks about something. It's often negative.
Usage
Written: 
No
Spoken: 
Yes
Formal: 
No
Informal: 
Yes
Example 1
I get so bored talking to Nigel. All he's interested in is football.
I know. He's got football on the brain.
Example 2
Are you coming to the party on Friday? Donna will be there. Donna's great.
Will you shut up about Donna! You've got her on the brain!

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