ku-adjective (archaic)
Archaic -ku adjective meaning something is unforeseen or surprising. Not used in modern Japanese; found only in classical texts.
In classical texts, 念無し was written to mean 'unexpected'.
ku-adjective (archaic)
Archaic -ku adjective expressing regret or disappointment. Obsolete in modern usage.
ku-adjective (archaic)
Archaic -ku adjective meaning something is simple or effortless. This sense is not found in modern Japanese.
ku-adjective (archaic)
without regrets
Archaic -ku adjective indicating a state of having no regrets. Entirely obsolete.
The archaic word 念無し also had the meaning 'regrettable'.
Examples of 念無し used to mean 'easy' are limited to old documents.
In classical Japanese dictionaries, 念無し is glossed as 'without regrets'.
The exact derivation is uncertain. The kanji 念 (thought, concern) and 無し (without) suggest a literal meaning of 'without concern,' which may have given rise to the various archaic senses.