on fire

Prepositional phrase

1. Being burned by fire.
   • If the wind picks up and the flames spread, the whole town could go on fire.

   Synonyms:

   afire, aflame, alight, burning, flaming, in flames, go up in smoke

2. (idiomatic) Overwhelmed with emotion; beside oneself.
   • Anytime I am on fire with anxiety about the future, or totally freaking out that I am not being seen, heard, or treated fairly based on my old wounds, it is easy for me to RECOGNIZE that my Character 2 has flared right up in an attempt to not only protect me but help me get my needs met.2022 [2021], Jill Bolte Taylor, “The Brain Huddle: Your Power Tool for Peace”, in Whole Brain Living: The Anatomy of Choice and the Four Characters That Drive Our Life, Carlsbad, CA: Hay House...
3. (idiomatic) Excited, enthusiastic or passionate.
   • “I'm on fire with an idea,” the 48-year-old businessman proclaimed with excitement similar to that which he projected in 1971 when his company became the first predominantly Black-owned corporation to be listed on the American Stock Exchange.1975 November 6, Robert E. Johnson, “The Prodigal Returns To His First Love: The Beauty Industry”, in Jet, volume 49, number 7, page 21
4. (idiomatic) Doing very well; achieving good results at a rapid rate.
   • That striker has scored four goals so far – he's on fire!

   Synonyms:

   on a roll, on a tear

5. (idiomatic, informal) Sexually aroused.
6. (excessive) Experiencing a burning-like sensation, especially "the burn" (from buildup of lactic acid)
   • He locks us into a crouched position that results in muscle failure of the quads, hamstrings, and calves. It hurts. We raise ten-pound rubber rifles and hold them parallel to the ground. Our legs are on fire, then our arms too.2016, Eric Fair, Consequence, page 28