Lewis & Short

ăcapnos, on, adj., = ἄκαπνος, without smoke: ligna acapna, wood so dry as to emit no smoke in burning, Mart. 13, 15: mel acapnon, honey obtained without driving away the bees by smoke, Col. 6, 33, 2; Plin. 11, 16, 15, § 45.