Obs. rare. [f. KEEN a.] trans. To render keen; to sharpen.
1599. H. Buttes, Dyets drie Dinner, Aa iij b. Now, lest thou keen thy blunted appetence.
c. 1689. Popish Pol. Unmaskt, 35, in 3rd Coll. Poems (1689), 23/1. You Cow the Bold, and Keen the Cowards heart.
1727–46. Thomson, Summer, 1259. When cold Winter keens the brightening flood.
