Men he's trained get in a tangle (6)
I believe the answer is:
enmesh
'get in a tangle' is the definition.
(I've seen this before)
'men he's trained' is the wordplay.
'trained' indicates anagramming the letters (to train can mean to grow something into a shape).
'men'+'hes'='menhes'
'menhes' is an anagram of 'ENMESH'.
(Other definitions for enmesh that I've seen before include "Catch in net" , "get in a tangle" , "Never growing old" , "Catch in toils" , "Make tangled as if in a net" .)