Property for guys, in principle (8)
I believe the answer is:
tenement
'property' is the definition.
(I've seen this before)
'guys in principle' is the wordplay.
'guys' becomes 'men' (guy can mean a man).
'in' is an insertion indicator.
'principle' becomes 'tenet' (a tenet is a principle or value).
'men' put within 'tenet' is 'TENEMENT'.
'for' is the link.
(Other definitions for tenement that I've seen before include "Run-down apartment house" , "Block of flats" , "Flat" , "Run-down house for many people" , "Large residential building" .)