Swell bugle two exchanged (5)
I believe the answer is:
bulge
'swell' is the definition.
(bulging is a kind of swelling)
'bugle two exchanged' is the wordplay.
'bugle' anagrams to 'BULGE'.
However, I am not sure how this is indicated.
Can you help me to learn more?
(Other definitions for bulge that I've seen before include "Swell" , "Protrusion" , "Swelling - sudden increase" , "Hump" , "surge?" .)