Fencing in if, again, it's rampant (4)
I believe the answer is:
rife
'rampant' is the definition.
(I've seen this in another clue)
'fencing in if again' is the wordplay.
I cannot quite see how this works, but
'if' is found in the answer.
'again' could be 're' (prefix meaning 'again') and 're' is present in the leftover letters.
No letters remain.
This explanation may well be incorrect...
'it's' acts as a link.
Can you help me to learn more?
(Other definitions for rife that I've seen before include "Widespread sort of fire" , "Widespread like fire" , "Very common or frequently occurring" , "Of widespread occurrence" , "Prevalent" .)