potently effective; proved effective (of medicine, advice, lesson, etc.) / effectively cutting through (of cutting tools)

potent effectiveness; effective action (of medicine, advice, lesson, etc.) / cutting action (of cutting tools) / act of blunting a tool / root used for dyeing

talking in a fast, loud voice (rapidly and continuously) / tsking (sound and act, usually as a sign of disapproval)

kans grass (Saccharum spontaneum)