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 really understand how this works, but
'if' is within the answer.
'again' could be 're' (prefix meaning 'again') and 're' is found within the remaining letters.
No letters remain.
This explanation may well be incorrect...
'it's' is the 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" .)