Hint of ecstasy found in open pub at first (8)
I believe the answer is:
innuendo
'hint' is the definition.
(I've seen this before)
'ecstasy found in open pub at first' is the wordplay.
'ecstasy' becomes 'E' (informal term for the drug).
'found in' indicates putting letters inside.
'open' becomes 'undo' (eg opening a bottle).
'pub' becomes 'inn' (an inn is a type of pub).
'at first' is a charade indicator (letters next to each other).
'e' going inside 'undo' is 'uendo'.
'uendo' after 'inn' is 'INNUENDO'.
'of' is the link.
(Other definitions for innuendo that I've seen before include "Rude suggestion" , "Implied smut" , "sneaky reference" , "An unpleasant insinuation or intimation" , "Disparaging oblique remark" .)