Struck lightly (6)
I believe the answer is:
tapped
'struck lightly' is the definition.
('tap' can be a synonym of 'strike lightly')
This is all the clue.
(Other definitions for tapped that I've seen before include "Intercepted (a phone)" , "Rapped lightly or drew upon" , "Struck lightly" , "Exploited (a resource)" , "Knocked; exploited" .)