Perhaps pet test is over (3)
I believe the answer is:
tom
'perhaps pet' is the definition.
The answer and definition can be both animals as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'test is over' is the wordplay.
'test' becomes 'MOT' (as in an MOT test for a vehicle).
'is over' says the letters should be written backwards.
'mot' in reverse letter order is 'TOM'.
Can you help me to learn more?
(Other definitions for tom that I've seen before include "Cruise" , "He is associated with Dick and Harry" , "What Dick Whittington had" , "Male beast" , "Pig-stealing piper's son" .)