Director's frilly neckwear tight on the outside (8)
I believe the answer is:
truffaut
'director's frilly' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'neckwear tight on the outside' is the wordplay.
'neckwear' becomes 'ruff' (I have seen 'Jacobean neckwear ' mean 'ruff' so perhaps 'neckwear' could also mean 'ruff').
'tight' becomes 'taut' (synonyms).
'on the outside' means one lot of letters goes inside another.
'ruff' inserted inside 'taut' is 'TRUFFAUT'.
Can you help me to learn more?
(Other definitions for truffaut that I've seen before include "Filmmaker" , "film director" , "Franois -, French film producer" .)