Pollsters impressed with a native New Zealander (5)
I believe the answer is:
maori
'native new zealander' is the definition.
(I've seen this before)
'pollsters impressed with a' is the wordplay.
'pollsters' becomes 'mori' (market research company Ipsos MORI).
'impressed with' indicates putting letters inside.
'mori' placed around 'a' is 'MAORI'.
(Other definitions for maori that I've seen before include "Member of New Zealand's aboriginal people" , "Polynesian aborigine" , "NZ people" , "NZ Polynesian language" , "native person" .)