The wit's as clean as could be (7)
I believe the answer is:
whitest
'clean as could be' is the definition.
I can't tell whether this defines the answer.
'the wit's' is the wordplay.
'the wit's' anagrams to 'WHITEST'.
However, I am unsure how this is indicated.
'as' acts as a link.
Can you help me to learn more?
(Other definitions for whitest that I've seen before include "Most pale" , "Having the least amount of colour" , "Superlatively clean" , "Cleanest" , "Having the least coloration" .)