Extremist often seen with Violet (5)
I believe the answer is:
ultra
'extremist' is the definition.
(ultra can mean an extremist or radical)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for ultra that I've seen before include "lacking moderation" , "Prefix meaning extreme or excessive" , "Prefix meaning beyond or extremely" , "Immoderate" , "Extreme - extremist" .)