Prepares for combat like touring marines (4)
I believe the answer is:
arms
'prepares for combat' is the definition.
'arms' can be an answer for 'prepares'. I'm not sure about the 'for combat' bit.
'like touring marines' is the wordplay.
'like' becomes 'as'.
'touring' indicates putting letters inside (touring can mean going round).
'marines' becomes 'RM' (abbreviation for 'Royal Marines').
'as' going around 'rm' is 'ARMS'.
Can you help me to learn more?
(Other definitions for arms that I've seen before include "International competition for weapons" , "Weapons, collectively" , "Protesting violently, up in these" , "branches" , "What the Venus de Milo lacks" .)