Unable to escape, resident finally knocked (7)

I believe the answer is:

trapped

I'm a little stuck... Click here to teach me more about this clue!

'unable to escape' is the definition.
I can't judge whether this definition defines the answer.

'resident finally knocked' is the wordplay.
'finally' indicates one should take the final letters.
'knocked' becomes 'rapped' ('rap' can be a synonym of 'knock').
The last letter of 'resident' is 't'.
't'+'rapped'='TRAPPED'

Can you help me to learn more?

(Other definitions for trapped that I've seen before include "Caught" , "in a tight corner" , "Ensnared, cornered" , "Stuck" , "Snared" .)

I've seen this clue in The Times.

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