Semi-solid lump (6)
I believe the answer is:
dollop
'semi-solid lump' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for dollop that I've seen before include "Small mass of eg cream" , "Large spoonful" , "Small, unmeasured amount" , "Blob" , "Small measure, of mash say" .)