Nameless character squeezes through opening (8)
I believe the answer is:
aperture
'opening' is the definition.
(I know that aperture is a type of hole)
'nameless character squeezes' is the wordplay.
I cannot really understand how this works, but
'character' could be 'pe' (pe is a kind of character) and 'pe' is located in the answer.
This explanation may well be incorrect...
'through' is the link.
(Other definitions for aperture that I've seen before include "Small hole or opening" , "Eye" , "Narrow opening" , "'Hole, opening (8)'" , "Opening (on camera, for example)" .)