Meaning of “but” - Learner’s Dictionary

but

conjunction uk us strong /bʌt/ weak /bət/
OPPOSITE INFORMATION

A1 used to introduce something new that you say, especially something that is different or the opposite from what you have just said:

I'd drive you there, but I don't have my car.
The tickets were expensive, but the kids really enjoyed it.
EXPLAINING WHY

used before you say why something did not happen or is not true:

I was going to go to his party, but I was sick.
SHOWING SURPRISE

used to show that you are surprised about what someone has just said:

'Tim is leaving.' 'But why?'
CONNECTING PHRASES

used to connect 'excuse me' or 'I'm sorry' with what you say next:

Excuse me, but would you mind shutting the door?

(Definition of “but conjunction” from the Cambridge Learner’s Dictionary © Cambridge University Press)