Swell connected to operator (7)
I believe the answer is:
surgeon
'to operator' is the definition.
(someone who operates)
'swell connected' is the wordplay.
'swell' becomes 'surge' (I've seen this before).
'connected' becomes 'on' (synonyms).
'surge'+'on'='SURGEON'
(Other definitions for surgeon that I've seen before include "Theatre worker" , "One who operates" , "Physician" , "Operating medical practitioner" , "Theatre operator" .)