Extremists in innermost Nicaragua backing Contra (4)
I believe the answer is:
anti
'contra' is the definition.
(I've seen this in another clue)
'extremists in innermost nicaragua backing' is the wordplay.
'extremists in' says to hollow out the word (remove centre letters).
'nicaragua' becomes 'na' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'backing' is a reversal indicator.
'innermost' with its centre taken out is 'it'.
'it'+'na'='itna'
'itna' backwards is 'ANTI'.
Can you help me to learn more?
(Other definitions for anti that I've seen before include "Not favouring" , "'No' voter" , "[NO MAN]" , "Who pooh-poohs all" , "Prefix meaning against" .)