Opposing (4)
'opposing' is the definition.
(eg opposing in war)
This is the entire clue.
(Other definitions for against that I've seen before include "Disapproving of" , "V" , "Placed in direct contact with" , "Opposite to" , "on the other side" .)
'opposing' is the definition.
(resisting is a kind of opposing)
This is all the clue.
(Other definitions for resisting that I've seen before include "Withstanding" , "smart, that!" , "Refraining from" .)
'opposing' is the definition.
(prefix meaning 'opposing')
This is the entire clue.
(Other definitions for anti that I've seen before include "Not favouring" , "Opposition member" , "Definitely not pro" , "Someone opposed (to a policy?)" , "An opponent - opposed to party policy, etc" .)