eagerly; intently; single-mindedly
Describes doing something with undivided attention, without distraction or other thoughts. Somewhat literary.
He devoted himself single-mindedly to his research.
The children were absorbed in play, without a thought for anything else.
Focuses on being absorbed in something enjoyable; 他念無く emphasizes the lack of other thoughts.
Standard kanji spelling for this adverb.
Alternate kanji spelling; 無く is more common than なく in formal writing.
From 他念 (other thoughts) + 無く (without). The exact historical derivation is uncertain, but the meaning is transparent from its components.