タレこむ

た

れ

こ

む

タレこむ · godan verb (-mu)

Meanings

godan verb (-mu), transitive verb

tip off; inform on; squeal; rat out

usually written using kana alone

Informal, often used for reporting someone to authorities or superiors. It is usually written in kana.

密みっ告こく
密告 is a more formal term for informing on someone, often used in legal or official contexts, while タレこむ is slangy and informal.
垂たれ込こめる
垂れ込める means 'to hang low (clouds, fog, etc.)' and is a different verb, though it shares the same kanji spelling as the rare form of タレこむ.

タレこむ
kana-only spelling
Common kana spelling; usually written in kana.
たれ込こむUsage36%
search-only kanji form
たれこむUsage32%
Hiragana spelling, also common.
タレ込こむUsage25%
search-only kanji form
垂たれ込こむUsage7%
Kanji spelling is rare and may be confused with the homograph 垂れ込む (たれこむ) meaning 'to hang low (clouds, etc.)'.

The exact derivation is uncertain. It may be related to 垂れる (たれる, 'to hang down') with a sense of 'dropping' information, but this is speculative.