godan verb (-su), transitive verb
to tire out; to exhaust
Archaic transitive verb meaning to make someone tired or to exhaust them. In modern Japanese, 疲れさせる or 疲れさす are used instead.
古文では「人を疲らかす」のように使われた。
In classical Japanese, it was used like 'to tire a person out'.
Derived from 疲れる (つかれる, 'to get tired') with the archaic causative suffix かす, forming a transitive verb meaning 'to make tired'. The exact historical development is uncertain.