Open old criminal's cabinet up and gasp at inhabitant (8)
I believe the answer is:
occupant
'inhabitant' is the definition.
(I know that occupant is a type of inhabitant)
'open old criminal's cabinet up and gasp' is the wordplay.
'open' says to take the initial letters (take the opening letter).
'and' is a charade indicator (letters next to each other).
'gasp' becomes 'pant' (synonyms).
The initial letters of 'old criminals cabinet up' is 'occu'.
'occu'+'pant'='OCCUPANT'
'at' is the link.
(Other definitions for occupant that I've seen before include "Homeowner or tenant" , "Insider" , "Inhabitant, resident" , "One holding position or residing in house" , "Inmate" .)