Unlikely to run like Usain Bolt, perhaps (4)
I believe the answer is:
fast
'unlikely to run' is the definition.
(I've seen this before)
'like usain bolt perhaps' is the wordplay.
I cannot quite understand how this works, but
'like' could be 'as' and 'as' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for fast that I've seen before include "Starve; quick" , "Firm < moving rapidly" , "Don't scoff" , "sort of convenience food" , "Abstain from eating" .)