Blast on site is most deafening (8)
I believe the answer is:
noisiest
'most deafening' is the definition.
Both the answer and definition are superlative adjectives. Perhaps you can see a link between them that I don't see?
'blast on site is' is the wordplay.
'on site is' anagrams to 'NOISIEST'.
However, I am unsure how this is indicated.
Can you help me to learn more?
(Other definitions for noisiest that I've seen before include "Making the loudest sounds" , "Making the most loud sounds" , "Biggest racket" , "party being at this extreme?" , "Making the most sound" .)