Most vulgar neckties are from factories exporting sartorial tools originally (7)
I believe the answer is:
naffest
'most vulgar' is the definition.
Both the answer and definition are superlative adjectives.
Perhaps you can see an association between them that I can't see?
'neckties are from factories exporting sartorial tools originally' is the wordplay.
'originally' says to take the initial letters.
The initial letters of 'neckties are from factories exporting sartorial tools' is 'NAFFEST'.
Can you help me to learn more?
(Another definition for naffest that I've seen is " in the worst possible taste".)