flammable /ˈflæməbl̩/adjective 4noun 1forms 3 adjective4 •Capable of burning. •Easily set on fire. •Subject to easy ignition and rapid flaming combustion. •(figurative) Very likely to cause fighting or controversy; extremely contentious.They could stuff their ears with cotton, but they could not, after all, fight such flammable ideas ( at least not in the public squares where Attucks's war whoops could still be heard ). — 2002 noun1 •Any flammable substance. formsflammables · more flammable · most flammable