suffix
Productive suffix that attaches to nouns or verb stems to form agent nouns or role nouns. Common in compounds like 医者, 学者, 読者.
彼は有名な科学者です。
He is a famous scientist.
この本は多くの読者に愛されている。
This book is loved by many readers.
noun
Archaic abbreviation of 其れ者 (それしゃ) or similar compounds. Used historically to refer to a specialist, a geisha, or a prostitute. Not productive in modern Japanese.
See also: 其れ者
江戸時代には、「者」だけで芸者や遊女を指すことがあった。
In the Edo period, 者 alone could refer to a geisha or a courtesan.
人 is a general noun for 'person', while 者 is a suffix that creates agent nouns or role nouns.
家 is a suffix for 'specialist' or 'professional' (e.g., 作家, 画家), often overlapping with 者 but with a stronger nuance of expertise.
From Chinese 者 (zhě), a nominalizing suffix. In Japanese, it became a productive suffix for agent nouns and was also used as an archaic standalone noun for certain professions.