Admirable woman last to go for drug (6)
I believe the answer is:
heroin
'for drug' is the definition.
(heroin is a kind of drug)
'admirable woman last to' is the wordplay.
I cannot really see how this works, but
'woman' could be 'her' (her refers to a woman) and 'her' is found within the answer.
This may be the basis of the clue (or it may be nonsense).
'go' acts as a link.
Can you help me to learn more?
(Other definitions for heroin that I've seen before include "Highly addictive illegal drug" , "Class A drug" , "Narcotic powder derived from morphine" , "Highly addictive narcotic" , "Highly addictive morphine derivative" .)