antagonist
noun /ænˈtæɡənɪst/
/ænˈtæɡənɪst/
(formal)- a person who strongly opposes somebody/something synonym opponent
- He has always been the prime minister’s most formidable antagonist in Parliament.
Word Originlate 16th cent.: from French antagoniste or late Latin antagonista, from Greek antagōnistēs, from antagōnizesthai ‘struggle against’, from ant- ‘against’ + agōnizesthai ‘struggle’ (from agōn ‘contest’).