1chiefly
British having or showing eagerness or enthusiasm:a keen gardener John was keen to help (
keen on)
interested in or attracted by (someone or something):Bob makes it obvious he’s keen on her
2sharp or penetrating, in particular: (of a sense) highly developed:I have keen eyesight (of mental faculties) quick to understand:her keen intellect (of the edge or point of a blade) sharp: the keen blade went through the weeds (of the air or wind) extremely cold; biting: a keen wind cut through their thick overalls literary (of a smell, light, or sound) penetrating; clear: ear-splitting explosive bursts, keen and sharp
3British (of activity or feeling) intense:there could be keen competition to provide the service 3(of prices) very low; competitive: we offer extremely keen rates
4 [predic.] North American informal,
dated excellent: I would soon fly to distant stars—how keen!