taru-adjective, adverb taking the 'to' particle
earnestly and patiently; repeatedly and persistently
Describes the manner of explaining, admonishing, or advising someone with earnest repetition and patience. Often used in literary or formal contexts with the と particle.
The teacher patiently and repeatedly gave the student warnings.
He continued to persuade earnestly and persistently.
Standard kanji spelling using the repetition mark 々.
Alternate spelling without the repetition mark; less common but attested.
The exact derivation is uncertain. The kanji 諄 carries the meaning of 'repetitious' or 'tedious', and the reduplication reinforces the sense of repeated, patient admonition.