Worthy old relative drugs grasping duke (7)
I believe the answer is:
grandee
'worthy old' is the definition.
Although both the answer and definition are singular nouns, I can't see how they can define each other.
'relative drugs grasping duke' is the wordplay.
'relative' becomes 'gran' (short for grandmother).
'drugs' becomes 'ee' (an abbreviation for ecstasy written twice).
'grasping' means one lot of letters goes inside another.
'duke' becomes 'd' (abbreviation).
'gran'+'ee'='granee'
'granee' placed around 'd' is 'GRANDEE'.
Can you help me to learn more?
(Other definitions for grandee that I've seen before include "One of high rank" , "Angered over Spanish noble" , "Spanish bigwig" , "Person of eminence" , "Eminent man" .)