adj., v., & n.
adj. 1 candid, outspoken (a frank opinion). 2 undisguised, avowed (frank admiration). 3 ingenuous, open (a frank face). 4 Med. unmistakable.
v.tr. 1 stamp (a letter) with an official mark (esp. other than a normal postage stamp) to record the payment of postage. 2 hist. superscribe (a letter etc.) with a signature ensuring conveyance without charge; send without charge. 3 archaic facilitate the coming and going of (a person).
n. 1 a franking signature or mark. 2 a franked cover. frankable adj. franker n. frankness n.
[ ME f. OF franc f. med.L francus free, f. FRANK (since only Franks had full freedom in Frankish Gaul) ]