Who boarded the tramp in it? (4)

I believe the answer is:

hobo

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'it?' is the definition.
I can't tell whether this defines the answer.

'who boarded the tramp in' is the wordplay.
'in' indicates a hidden word.
'HOBO' can be found hidden inside 'who boarded tramp'.

Can you help me to learn more?

(Other definitions for hobo that I've seen before include "Vagrant (American)" , "Vagrant, tramp" , "American tramp" , "Homeless American" , "Tramp (US)" .)

I've seen this clue in the Evening Standard.

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