Promise to hem edges of teenage clothing item (7)

I believe the answer is:
sweater
'clothing item' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I can't see?
'promise to hem edges of teenage' is the wordplay.
'promise' becomes 'swear' (as in swearing something is true).
'to hem' is an insertion indicator (hem can mean to enclose).
'edges of' says to hollow out the word (remove centre letters).
'teenage' with its middle removed is 'te'.
'swear' going around 'te' is 'SWEATER'.
Can you help me to learn more?
(Other definitions for sweater that I've seen before include "Woolly" , "Long-sleeved pullover" , "Warm garment" , "Jumper (7)" , "Heavy jersey" .)
