protagonist
noun
Origin:
late 17th century: from Greek prōtagōnistēs, from prōtos 'first in importance' + agōnistēs 'actor'
The first sense of protagonist, as originally used in connection with ancient Greek drama, is ‘the main character in a play.’ In the early 20th century, a new sense arose meaning ‘a supporter of a cause’: a strenuous protagonist of the new agricultural policy. This new sense probably arose by analogy with antagonist, the pro- in protagonist being interpreted as meaning ‘in favor of.’ In fact, the prot- in protagonist derives from the Greek root meaning ‘first.’ Protagonist is best used in its original dramatic, theatrical sense, not as a synonym for supporter or proponent. Further, because of its basic meaning of ‘leading character,’ such usage as the play’s half-dozen protagonists were well cast blurs the word’s distinctiveness; characters, instead of protagonists, would be more precise.