Hit by small cycle (6)
I believe the answer is:
strike
'hit' is the definition.
('strike' can be a synonym of 'hit')
'small cycle' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'cycle' becomes 'trike' (trike is a kind of cycle).
's'+'trike'='STRIKE'
'by' acts as a link.
(Other definitions for strike that I've seen before include "Failure to hit ball" , "Agree on" , "Hit forcibly" , "Walk out" , "Sudden attack; chime" .)