About time for pet (3)
I believe the answer is:
cat
'for pet' is the definition.
(cats are often kept as pets)
'about time' is the wordplay.
'about' becomes 'ca' (abbreviation for circa).
'time' becomes 't' (abbreviation).
'ca'+'t'='CAT'
(Other definitions for cat that I've seen before include "Common pet" , "Moggy" , "Carnivore; whip" , "Tabby" , "Feline - whip" .)