Dad's in the top apartment (4)

I believe the answer is:

papa

'dad's' is the definition.
(synonyms)

'in the top apartment' is the wordplay.
'in' indicates a hidden word.
'PAPA' is hidden within 'top apartment'.

(Other definitions for papa that I've seen before include "The old man" , "Pop" , "Mama's other half?" , "Comms code for 'P'" , "Father; P (radio comms.)" .)

I've seen this clue in the Evening Standard.

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