IPA: /əˈplɔːdə/
KK: /əˈplɔːdər/
A person who shows approval or praise by clapping their hands.
The applauder cheered loudly after the performance.
Applauder is formed from "applaud" (from Latin "applaudere", meaning to strike upon or clap) and "-er" (meaning a person who). The word refers to a person who claps or shows approval, typically in a performance context.
Think of someone who 'claps' ('applaud') to show approval — the '-er' indicates that this person is doing the action.