One occupying which rotten antiquated house? (6)
I believe the answer is:
Here is my best explanation:
'one occupying' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'which rotten antiquated house?' is the wordplay.
'house?' says the answer is hidden in the clue (I've seen 'houses' mean this (part of the clue houses the answer)).
'TENANT' can be found hidden inside 'which rotten antiquated'.
(Other definitions for tenant that I've seen before include "A rent payer", "Anne Bronte's novel 'The ...... of Wildfell Hall'", "Rent-payer", "One who pays the landlord", "Renting occupant", "one paying rent", "Occupier of rented property", "individual bound by lease", "Person renting property" and "Renter of property".)