Monumental spread maybe gripping pollsters (8)
I believe the answer is:
memorial
'monumental' is the definition.
(thesaurus)
'spread maybe gripping pollsters' is the wordplay.
'spread maybe' becomes 'meal' (I've seen this in another clue).
'gripping' is an insertion indicator (inserted letters are gripped).
'pollsters' becomes 'mori' (market research company Ipsos MORI).
'meal' placed around 'mori' is 'MEMORIAL'.
(Other definitions for memorial that I've seen before include "Commemorative object" , "statement of facts" , "Statue or monument that commemorates" , "Relic, monument" , "may be brass" .)