- Go to Setup > Organization Settings > System.
- Under Sport Settings, find Word For Player, Word for Volunteer.
- In the corresponding fields, change the names to what you desire.
- Once complete, click Save - at the bottom of the screen.
NOTE: Below are popular/potential replacements for the default system diction.
- Player: Participant.
- Volunteer: Associate (although it is recommended to rather, set up a custom registration role).