A gourmand initially fat is stuck (7)
I believe the answer is:
aground
'is stuck' is the definition.
(thesaurus)
'a gourmand initially fat' is the wordplay.
'initially' says to take the initial letters.
'fat' becomes 'round' (round can mean fat or plump).
The first letter of 'gourmand' is 'g'.
'a'+'g'+'round'='AGROUND'
(Other definitions for aground that I've seen before include "on rocks, perhaps" , "No longer floating" , "High and dry" , "on the bed" , "On guard (anag.)" .)