Determined to scrap auctions involving ecstasy (9)
I believe the answer is:
tenacious
'determined' is the definition.
(I've seen this before)
'scrap auctions involving ecstasy' is the wordplay.
'scrap' is an anagram indicator (I've seen 'scrapped' mean this).
'involving' means one lot of letters goes inside another.
'ecstasy' becomes 'E' (informal term for the drug).
'auctions' is an anagram of 'tnacious'.
'tnacious' enclosing 'e' is 'TENACIOUS'.
'to' is the link.
(Other definitions for tenacious that I've seen before include "Determined" , "Persevering" , "Dogged" , "Holding fast" , "refusing to give up" .)