Old stunted professor kept in loop, partly? (7)
I believe the answer is:
archaic
'old' is the definition.
(similar in meaning)
'stunted professor kept in loop partly?' is the wordplay.
'stunted' means to remove the last letter (the word is shorter than it usually is).
'professor' becomes 'chair' (chair can mean a professorship).
'kept in' is an insertion indicator.
'loop partly?' becomes 'arc' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'chair' with its final letter removed is 'chai'.
'chai' placed within 'arc' is 'ARCHAIC'.
Can you help me to learn more?
(Other definitions for archaic that I've seen before include "Of a much earlier period" , "Obsolete" , "No longer in general use" , "Belonging to former times, perhaps word usage" , "A long way out of date" .)