Hit by stone joining melee (6)
I believe the answer is:
struck
'hit' is the definition.
(strike can mean to hit)
'by stone joining melee' is the wordplay.
'by' says to put letters next to each other.
'stone' becomes 'st' (abbreviation).
'joining melee' becomes 'ruck' (I can't justify this - if you can you should give a lot more credence to this answer).
'st'+'ruck' is 'STRUCK'.
Can you help me to learn more?
(Other definitions for struck that I've seen before include "Impressed with, as by blow?" , "dismantled" , "Hit or impressed" , "Hit as by lightning" , "Delivered a sharp blow" .)