Noun firebug has 2 senses
  1. arsonist, incendiary, firebug - a criminal who illegally sets fire to property
    --1 is a kind of criminal, felon, crook, outlaw, malefactor
    --1 has particulars: barnburner
  2. firebug - a true bug: brightly colored bug that can exude a stain
    --2 is a kind of
    heteropterous insect
    --2 is a member of Pyrrhocoridae, family Pyrrhocoridae