Tom rises to the test (3)
I believe the answer is:
mot
'the test' is the definition.
(as in an MOT test for a vehicle)
'tom rises' is the wordplay.
'rises' shows that the letters should be reversed in order.
'tom' written backwards gives 'MOT'.
'to' acts as a link.
(Other definitions for mot that I've seen before include "Word in France, bon perhaps" , "Wisecrack (for older cars!)" , "French word for Tom" , "Clever remark" , "type of test" .)