Extreme gluttony, eating hard marrow - taste pungent? (8)
'pungent?' is the definition.
('garlicky' can be similar in meaning to 'pungent')
'extreme gluttony eating hard marrow taste' is the wordplay.
I cannot really see how this works, but
'taste' could be 'lick' (I've seen this before) and 'lick' is located in the answer.
The remaining letters 'gary' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for garlicky that I've seen before include "tasting of cloves?", "Strong-smelling", "Likely to cause bad breath when eaten?", "somewhat pungent".)