What we have is time, according to the cockney (4)
I believe the answer is:
ours
'what we have' is the definition.
(I've seen this in another clue)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for ours that I've seen before include "British" , "Relating or belonging to us" , "Indiscriminate slaughter" , "The French bear" , "of the Queen?" .)