Knobbly; clotted (5)
I believe the answer is:
lumpy
I believe this clue is a double definition.
'knobbly' is the first definition.
(I've seen this before)
'clotted' is the second definition.
(thesaurus)
(Other definitions for lumpy that I've seen before include "Not smooth" , "Covered in swellings" , "Choppy" , "As badly mixed custard" , "Clotted; knobbly" .)