か弱い[kayowai] frail
ひ弱い[hiyowai] weak
意志薄弱[ishihakujaku] weak-willed
胃弱[ijaku] dyspepsia
虚弱[kyojaku] feebleness

強弱[kyoujaku] strength
弱い[yowai] weak
弱い者[yowaimono] weak person
弱い相互作用[yowaisougosayou] weak interaction (physics)