The Collaborative International Dictionary of English v.0.48:

flameproof \flameproof\ adj.
   not susceptible to burning; noncombustible; fireproof; -- of
   artifacts. Opposite of combustible.

   Syn: flame-retardant.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

flameproof
    adj 1: resistant to catching fire [syn: flameproof, flame-
           retardant]

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "flameproof":
   airtight, ballproof, bombproof, bulletproof, burglarproof,
   corrosionproof, dampproof, fire-resistant, fire-resisting,
   fire-retardant, fire-retarded, fireproof, fireproofed, foolproof,
   hermetic, holeproof, impervious to, leakproof, noiseproof, proof,
   proof against, punctureproof, resistant, rustproof, shatterproof,
   shellproof, soundproof, tight, watertight, weatherproof