Elementary (A2)
IPA: /nɒnˈpɑːtɪsənt/
KK: /nɑnˈpɑrtɪsənt/
Definition
Not taking part in an activity or event.
Example
The nonparticipant observed the game from the sidelines.
Conversation

I noticed that during the game, there were several nonparticipant players on the bench.

Yeah, it’s always interesting to see who gets a chance to play.

I wonder if they feel left out being a nonparticipant in such an exciting match.

Probably, but they can still learn a lot just by watching.
Synonyms & Antonyms
Antonyms
engaged
involved
participating
Definition
A person who does not take part in an activity or event.
Example
She was a nonparticipant in the discussion, choosing to listen instead.
Conversation

Did you see that game last night?

Yeah, it was intense! I felt like a nonparticipant just watching.

I know what you mean; sometimes I wish I could join in.
Root Explanation
Nonparticipant → It is formed from "non-" (meaning not) and "participant" (from Latin "participare", meaning to take part). The word "nonparticipant" means someone who does not take part in an activity or event.
Memory Tip
Think of 'not' ('non-') being added to 'taking part' ('participate') — that's why a nonparticipant is someone who does not take part.
Visually Confused Words
unparticipant
participant
participantly
participate