the.com/contestant

means A person who formally enters a competition or contest, typically to vie for a prize or title.

from From 'contest,' tracing back to Latin 'contestari' — literally 'to call witnesses to' — built from 'con-' (together) and 'testari' (to testify, from testis, witness). Roman litigants would formally 'call witnesses' to open a legal dispute, and that sense of a formally joined struggle drifted from courtrooms to battles to, eventually, game shows. The '-ant' ending simply marks the one doing the contesting — the person who shows up to be tested, witnessed, and judged.