Pruritus (4)
I believe the answer is:
itch
'pruritus' is the definition.
(I know that pruritus can be written as Itch)
This is all the clue.
(Other definitions for itch that I've seen before include "Something that needs a scratch" , "Hunger, longing" , "Constant desire" , "Niggling skin sensation" , "Prickling" .)