Parrot maybe left in old college (5)
I believe the answer is:
polly
'parrot' is the definition.
(I've seen this before)
'left in old college' is the wordplay.
'left' becomes 'l' (common abbreviation).
'in' means one lot of letters goes inside another.
'old college' becomes 'poly' (polytechnic).
'l' inserted inside 'poly' is 'POLLY'.
'maybe' acts as a link.
(Other definitions for polly that I've seen before include "Parrot's name" , "Parrot; girl's name" , "- - Toynbee, columnist" , "' 197> - put the kettle on'" , "This Mr's history, H. G. Wells" .)