A bit wet? Emphatically not I! (4)
I believe the answer is:
most
'emphatically not i' is the definition.
The definition and answer can be both quantities as well as being singular nouns.
Perhaps you can see an association between them that I don't see?
'a bit wet?' is the wordplay.
I cannot quite see how this works, but
'bit' could be 'o' (resembles 0, a binary digit or bit) and 'o' is found in the answer.
The remaining letters 'mst' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for most that I've seen before include "Kind of commercial pact where two countries agree to treat each other as well as any other" , "Almost all" , "Greatest in amount or degree" , "In the highest degree" , "Nearly all, majority" .)