ku-adjective (archaic)
Archaic classical Japanese adjective (ク活用). Equivalent to modern 堅い/固い/硬い (かたい). Found in classical texts; not used in modern speech.
See also: 堅い
「石は堅し」と古の書にあり。
In an old text, it says 'the stone is hard'.
Classical Japanese adjective. The modern form かたい developed through regular sound changes from the archaic かたし.