Hit second lorry (6)
I believe the answer is:
struck
'hit' is the definition.
(I've seen this before)
'second lorry' is the wordplay.
'second' becomes 's' (common abbreviation).
'lorry' becomes 'truck' (I've seen this before).
's'+'truck'='STRUCK'
(Other definitions for struck that I've seen before include "Punched" , "Impressed with, as by blow?" , "Walloped" , "hit hard" , "Female relative" .)