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fire up (third-person singular simple present fires up, present participle firing up, simple past and past participle fired up)

1. (transitive) To ignite.

   Synonyms: inflame, kindle; see also Thesaurus:kindle

   Let's fire up the grill and have a barbecue.

   • 2025 September 23, Donald Trump, speech at United Nations:

     They're[renewables] not strong enough to fire up the plants that you need to make your country great. The wind doesn't blow. Those big windmills are so pathetic and so bad, so expensive to operate, and they have to be rebuilt all the time and they start to rust and rot.

2. (intransitive) Of an engine or similar, to start.

   Synonyms: fire, start up

   The generator fired up shortly after the power failure began.

3. (transitive, computing, informal) To launch; to run.

   Synonyms: activate, start up

   Fire up a text editor.

   Fire up your computer.

4. (transitive) To excite; to infuse with energy.

   Synonyms: ginger up, spice up; see also Thesaurus:enliven

   The band went out to fire up the crowd before the game.

5. (intransitive, dated) To grow irritated or angry.

   Synonym: anger

   • 1911, Thomas Babington Macaulay, “Bunyan, John”, in 1911 Encyclopædia Britannica‎^[1]:

     He […] fired up, and stood vigorously on his defence.

• ⇒ Greek: φαερόπ (faeróp) (as adverb)

• fur pie