Architect's endless list (8)
I believe the answer is:
inventor
'architect's' is the definition.
(thesaurus)
'endless list' is the wordplay.
'endless' means to remove the last letter.
'list' becomes 'inventory' (inventory is a kind of list).
'inventory' with its last letter taken away is 'INVENTOR'.
(Other definitions for inventor that I've seen before include "Discoverer" , "Morse, perhaps" , "Designer" , "Bell, say" , "The first one to make something" .)