Dr No, I suspect, seen in ad for robot (7)
I believe the answer is:
android
'for robot' is the definition.
(android is a kind of robot)
'dr no i suspect seen in ad' is the wordplay.
'suspect' is an anagram indicator (a suspicious or unusual spelling).
'seen in' is an insertion indicator.
'dr'+'no'+'i'='drnoi'
'drnoi' is an anagram of 'ndroi'.
'ndroi' put into 'ad' is 'ANDROID'.
(Other definitions for android that I've seen before include "Being not exactly human" , "Human-seeming robot" , "Automaton resembling a human" , "Operating system for mobile devices" , "Mechanical man" .)