Sallow old man on street, young initially (5)
I believe the answer is:
pasty
'sallow' is the definition.
(thesaurus)
'old man on street young initially' is the wordplay.
'old man' becomes 'pa' (both can mean father).
'on street' becomes 'st' (I've seen this in other clues).
'initially' suggests taking the first letters.
The initial letter of 'young' is 'y'.
'pa'+'st'+'y'='PASTY'
(Other definitions for pasty that I've seen before include "little pie" , "Meat and veg pie" , "Pallid" , "Meat-filled pastry dish" , "Cornish pie" .)