Flames are terribly rife (4)
I believe the answer is:
fire
'flames' is the definition.
(I've seen this in another clue)
'terribly rife' is the wordplay.
'terribly' indicates anagramming the letters.
'rife' with letters rearranged gives 'FIRE'.
'are' is the link.
(Other definitions for fire that I've seen before include "See 5" , "Trigger" , "Flame - dismiss - shoot" , "Shoot; sack" , "Weaponry" .)