fire, to be on Copy link Outline 1. ardeo, si, sum, 2 (most gen. term)2. flāgro, 1 (to be in a blaze) • fire, to be on: 1. ardeo, si, sum, 2 (most gen. term): the house was on f., domus ardebat, Cic.: when your neighbour's house is on f., paries quum proximus ardet, Hor. Ep. 1, 18, 84. Fig.: he foamed at the mouth, his eyes were on f., spumas agebat in ore, ardebant oculi, Cic.: all Spain would be on f. with war, totam Hispaniam arsuram bello, Liv. 28, 24, extr.: to be on f. with love, passion, etc., amore, cupiditate a., Cic.: Ter. 2. flāgro, 1 (to be in a blaze): you saw the transports on f., flagrantes onerarias videbatis, Cic. Div. 1, 32, 69. Fig.: to be on f. with love, hatred, amore, odio f., Cic. See also to blaze, be burnt.