Very uncommon (4)
I believe the answer is:
rare
'very uncommon' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rare that I've seen before include "like Ben Jonson, Jack Young thought" , "Very infrequent, lightly cooked" , "Not easily come by like undercooked meat" , "Very scarce, hardly cooked" , "Might a four-leaf clover be so" .)