protagonist
/prəʊˈtægənɪst/noun
1- the leading character or one of the major characters in a drama, film, novel, or other fictional text（戏剧、电影、小说等的）主人公。
1.1
- the main figure or one of the most prominent figures in a real situation主导者, 重要人物：
in this colonial struggle the main protagonists were Great Britain and France.
这场殖民战争中的主角是大不列颠和法国。
1.2
- an advocate or champion of a particular cause or idea（事业或观念的）提倡者; 拥护者：
a strenuous protagonist of the new agricultural policy.
新农业政策的热烈拥护者。
USAGE
The basic sense of protagonist, as originally used in connection with ancient Greek drama, is 'the main character in a play'. Some traditionalists object to the looser use to refer to a number of characters (rather than just the main one) in a play, film, etc., as for example the play's half-dozen protagonists were well cast, although this is both common and well established. Traditionalists also dislike the meaning 'a supporter of a cause', as in he's a strenuous protagonist of the new agricultural policy. This sense, recorded from the 19th century, probably arose by analogy with antagonist, the pro- in protagonist being interpreted as meaning 'in favour of'. In fact, prot- here derives from the Greek root meaning 'first'.
词源
late 17th cent.: from Greek prōtagōnistēs,from prōtos 'first in importance'+agōnistēs 'actor'.