Hit second load-bearing vehicle (6)
I believe the answer is:
struck
'hit second load' is the definition.
'struck' can be an answer for 'hit' (strike can mean to hit). I'm unsure of the 'second load' bit.
'bearing vehicle' is the wordplay.
'bearing' becomes 's'.
'vehicle' becomes 'truck' (truck is a kind of vehicle).
's'+'truck'='STRUCK'
Can you help me to learn more?
(Other definitions for struck that I've seen before include "Took industrial action" , "Hit - withheld labour" , "Hit; stopped work" , "stopped working" , "Hit, knocked with blow" .)