Rather watery prune mole eats (6)
I believe the answer is:
sloppy
'rather watery' is the definition.
'sloppy' can be an answer for 'watery' (thesaurus). I am unsure of the 'rather' bit.
'prune mole eats' is the wordplay.
I cannot really understand how this works, but
'prune' could be 'lop' (synonyms) and 'lop' is found in the answer.
'mole' could be 'spy' (I've seen this in another clue) and 'spy' is present in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for sloppy that I've seen before include "Careless and messy" , "Runny" , "Slipshod" , "Mawkish" , "'Careless, shoddy (6)'" .)