Squad not favoured to take on attack (6)
I believe the answer is:
outfit
'squad' is the definition.
(thesaurus)
'not favoured to take on attack' is the wordplay.
'not favoured' becomes 'out' (I've seen this before).
'to take on' means one lot of letters go next to another.
'attack' becomes 'fit' (fit is a kind of attack**).
'out'+'fit'='OUTFIT'
(Other definitions for outfit that I've seen before include "Costume" , "Team" , "Organisation or set of clothing" , "Set of clothes or group of people" , "Cohesive unit, eg a military company" .)