Skilfully coats item in liquid with 100% effectiveness (10)
I believe the answer is:
absolutely
'liquid with 100% effectiveness' is the definition.
I can't judge whether this definition defines the answer.
'skilfully coats item' is the wordplay.
'skilfully' becomes 'ably'.
'coats' is an insertion indicator (inserted letters are coated in another word).
'item' becomes 'solute' (I can't explain this - if you can you should believe this answer much more).
'ably' going around 'solute' is 'ABSOLUTELY'.
'in' acts as a link.
Can you help me to learn more?
(Other definitions for absolutely that I've seen before include "You bet!" , "Utterly" , "Totally" , "Yes, indeed!" , "Dead" .)