red-hot, 
piping hot, scorching (informal), boiling hot, fiery hot, sweltering, fiery, 
boiling, hot
antonym: cold
 
on 
fire, ablaze, blazing, flaming, smoldering, fiery 
strong, 
all-consuming, passionate, intense, fervent, ardent, fiery
antonym: weak
 
important, 
vital, crucial, urgent, significant, major
antonym: routine
 
smarting, 
stinging, tingly, prickly, painful 
feverish, 
flushed, hot, red, febrile, overheated, fevered
antonym: cool
  
arson, 
incendiarism (formal), pyromania, torching (slang), incineration, ignition, 
firebombing 
cremation, 
incineration, immolation (formal)