adverb, na-adjective
single-mindedly; intently; devotedly
Describes doing something with unwavering focus, putting all one's energy into it, often to the exclusion of other things. Can be used adverbially or as a na-adjective.
彼はひたすらに小説を書き続けた。
He kept writing his novel single-mindedly.
ひたすらな努力が実を結んだ。
His devoted efforts bore fruit.