light a fire under (someone)

: something that makes vision possible

: the sensation aroused by stimulation of the visual receptors

: electromagnetic radiation of any wavelength that travels in a vacuum with a speed of 299,792,458 meters (about 186,000 miles) per second

: having light : bright

: not dark, intense, or swarthy in color or coloring : pale

: medium in saturation and high in lightness

: to become light : brighten

: to take fire

: to ignite something (such as a cigarette)

: having little weight : not heavy

: designed to carry a comparatively small load

: having relatively little weight in proportion to bulk

: lightly

: with little baggage

: dismount

: settle, alight

: to fall unexpectedly

: the phenomenon of combustion manifested in light, flame, and heat

: one of the four elements of the alchemists

: burning passion : ardor

: to set on fire : kindle

: to give life or spirit to : inspire

: to fill with passion or enthusiasm

: in or into a position below or beneath something

: below or short of some quantity, level, or limit

: in or into a condition of subjection, subordination, or unconsciousness

: below or beneath so as to be overhung, surmounted, covered, protected, or concealed by

: subject to the authority, control, guidance, or instruction of

: receiving or undergoing the action or effect of

: lying or placed below, beneath, or on the ventral side

: facing or protruding downward

: lower in rank or authority : subordinate

: some person : somebody