Saint with selection, unusual (7)
I believe the answer is:
strange
'unusual' is the definition.
(I know that unusual can be written as strange)
'saint with selection' is the wordplay.
'saint' becomes 'st' (abbreviation).
'with' says to put letters next to each other.
'selection' becomes 'range' (a selection is a range of things).
'st'+'range'='STRANGE'
(Other definitions for strange that I've seen before include "Queer" , "Eccentric" , "Surreal" , "Offbeat" , "Different" .)