participant

One who participates.

Near-synonyms: entrant, partaker

All participants must adhere to the rules of the competition.

One who participates.

a research participant

In this study, participants were randomly assigned to either a control arm or a treatment arm.

Sharing; participating; having a share of part.

Therefore during the parliament he published his royal proclamation, offering pardon and grace of restitution to all such as had taken arms, or been participant of any attempts against him;