Glandular decay in professional (7)
I believe the answer is:
parotid
'glandular' is the definition.
Both the answer and definition are adjectives.
Perhaps there's a link between them I don't understand?
'decay in professional' is the wordplay.
'decay' becomes 'rot' (rot can mean to decay).
'in' means one lot of letters goes inside another.
'professional' becomes 'paid' (similar in meaning).
'rot' inserted within 'paid' is 'PAROTID'.
Can you help me to learn more?
(Another definition for parotid that I've seen is " Sort of duct".)