light a fire under

Related to light a fire under: alight

light a fire under (someone or something)

To motivate someone or something to take action. The deadline really lit a fire under us—we never would have gotten all that work done otherwise. Something must have lit a fire under Jenna—she has really started taking her schoolwork seriously.
See also: fire, light
Farlex Dictionary of Idioms.

light a fire under

Also, build a fire under. Urge or goad to action, as in If we don't light a fire under that committee, they'll never do any work. This hyperbolic colloquialism uses light in the sense of "ignite," a usage dating from the mid-1100s.
See also: fire, light
The American Heritage® Dictionary of Idioms by Christine Ammer.

light a fire under

To urge or move to action.
See also: fire, light
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • light a fire under (someone or something)
  • light a fire under someone
  • start a fire under (someone or something)
  • build a fire under (someone or something)
  • a fire under (someone or something)
  • draw a bead on (someone), to
  • keep after
  • keep after (someone or something)
  • put a bomb under
  • put a bomb under (someone or something)