Trap eccentric viewer (6)
I believe the answer is:
webcam
'viewer' is the definition.
I know nothing about this answer so I can't tell whether this works.
'trap eccentric' is the wordplay.
'trap' becomes 'web' (web is a kind of trap).
'eccentric' becomes 'cam' (eccentric cam is a type of mechanical part).
'web'+'cam'='WEBCAM'
Can you help me to learn more?
(Other definitions for webcam that I've seen before include "Internet-linked camera" , "Computer-linked imager" , "Digital camera" , "Internet spy" , "Digital viewer transmitting images live" .)