Walk-up dweller (6)
I believe the answer is:
tenant
'walk-up dweller' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for tenant that I've seen before include "Someone who pays rent" , "Occupier but not owner" , "He pays rent for lodgings" , "Anne Bronte's novel 'The ...... of Wildfell Hall'" , "One occupying rented property" .)