sympathizer
noun
[ ˈsɪmpəθʌɪzə ]
• a person who agrees with or supports a sentiment, opinion, or ideology.
• "a Nazi sympathizer"
Similar:
supporter,
advocate,
backer,
well-wisher,
ally,
partisan,
fellow traveller,
collaborator,
fraternizer,
conspirator,
quisling,
accomplice,
