taru-adjective, adverb taking the 'to' particle
Literary, somewhat archaic adverb describing steady, painstaking effort. Often used in the form 孜々として.
He devoted himself assiduously to his research.
His diligent work earned the respect of those around him.
assiduously; with unremitting zeal
Literary kanji form; the repetition mark 々 is standard for this word.
Alternate kanji form without the repetition mark; less common.
The exact derivation is uncertain; the kanji 孜 means 'industrious' or 'diligent', and the repetition emphasizes sustained effort. The word is a literary borrowing from classical Chinese.