It involves confused combatants (5)
I believe the answer is:
melee
'it involves confused combatants' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for melee that I've seen before include "A confused fight or muddle" , "Scrap" , "Confused fight or scuffle" , "Skirmish" , "Noisy riotous fight" .)