Thin -- not large? That makes sense (5)
I believe the answer is:
sight
'sense' is the definition.
(sighting is a kind of sensing)
'thin not large?' is the wordplay.
'thin' becomes 'slight' ('slight' can be similar in meaning to 'thin').
'not' suggests deleting specific letters.
'large?' becomes 'l'.
'slight' with 'l' taken out is 'SIGHT'.
'that makes' is the link.
(Other definitions for sight that I've seen before include "Vision, ability to see" , "Could be a jolly" , "Spot - eyesore" , "Seeing" , "A lot" .)