attender vs participant

attender and participant both are nouns.

Word	Noun	Adjective	Verb	Adverb
attender	Yes	No	No	No
participant	Yes	No	No	No

As nouns, participant is a hypernym of attender; that is, participant is a word with a broader meaning than attender:

Other hypernyms of attender include player.

attender (noun)	participant (noun)
someone who waits on or tends to or attends to the needs of another	someone who takes part in an activity
a person who is present and participates in a meeting	a person who participates in or is skilled at some game
someone who listens attentively