College almost left in shape (7)
I believe the answer is:
polygon
'shape' is the definition.
(I know that polygon is a type of plane figure)
'college almost left' is the wordplay.
'college' becomes 'poly' (polytechnic).
'almost' means to remove the last letter (most of the word but not all of it).
'left' becomes 'gone' (go can mean to leave).
'gone' with its final letter taken off is 'gon'.
'poly'+'gon'='POLYGON'
'in' is the link.
(Other definitions for polygon that I've seen before include "Straight-sided figure" , "Figure with many sides" , "Plane figure with a number of straight sides" , "Closed plane figure with three or more straight sides" , "shape" .)