noun
new member; entrant
Refers to a person who has recently joined a group, club, society, or organization.
今月の入会者は10名です。
There are ten new members this month.
新入生 is used for new students, whereas 入会者 is broader and can apply to any organization.
Compound of 入会 (にゅうかい, 'joining') + 者 (しゃ, 'person').