Obs. rare. [f. prec.: cf. OF. certainer, and ASCERTAIN.] trans. To make certain; to certify. Hence Certaining vbl. sb.
a. 1300. Cursor M., 26973. Bot if þat it be suilk a thing þat þou wat of na certanyng.
1523. Ld. Berners, Froiss., I. cclxx. 401. He certeyned them how he wolde ryde forthe.
