Entry 1 sense Webster, 1913 Knicker /nĭk'-ẽr/ · Knick·er · IPA /ˈnɪkə(ɹ)/ 01 n. A small ball of clay, baked hard and oiled, used as a marble by boys in playing. 1. A small ball of clay, baked hard and oiled, used as a marble by boys in playing.[Prov. Eng. & U. S.]