also: たれかれ
pronoun
anyone and everyone; this or that person; many people
Indefinite pronoun referring to people in general, often with a nuance of 'anybody at all' or 'various people'. Commonly used in set phrases like 誰彼となく (indiscriminately, to anyone).
誰彼となく声をかける。
He calls out to anyone and everyone.
誰彼の区別なく親切にする。
She is kind to all without distinction.
Kana spelling, often used in casual writing.
Mixed kanji-kana spelling, also common.
誰も is a negative polarity item meaning 'nobody' (with negative verb) or 'everyone' (with positive verb), while 誰彼 is an indefinite pronoun meaning 'anyone and everyone' without requiring a negative.
誰か means 'someone' (a specific but unknown person), whereas 誰彼 refers to people in general or indiscriminately.
Compound of 誰 (dare, 'who') and 彼 (kare, 'he' or 'that person'), literally 'who and that person', used to refer to people in general.