Crossword Genius

Went for a drive; may it have been clocked? (4,3)

Ross

I believe the answer is:

used car

'may it have been clocked?' is the definition.
(to clock a car is to falsely modify its milometer)

I cannot understand how the remainder of the clue works.

(Other definitions for used car that I've seen before include "Second-hand vehicle", "Previously-owned motor", "Second-hand motor".)

I've seen this clue in The Guardian.