Opponent of new technology diluted fluid (7)
I believe the answer is:
luddite
'opponent of new technology' is the definition.
(I've seen this before)
'diluted fluid' is the wordplay.
'fluid' is an anagram indicator.
'diluted' with letters rearranged gives 'LUDDITE'.
(Other definitions for luddite that I've seen before include "Person who opposes the introduction of new technology" , "Mechanisation resister" , "Diluted (anag) - opponent of technological innovation" , "Opponent of technological progress" , "One resisting technology progress" .)