light·ning 
(lītnĭng)
(lītnĭng)n.
1.
a. An abrupt, discontinuous natural electric discharge in the atmosphere.
b. The visible flash of light accompanying such a discharge.
2. Informal A sudden, usually improbable stroke of fortune.
intr.v. light·ninged (-nĭngd), light·ning, light·nings
To discharge a flash of lightning.
adj.
Moving or occurring with remarkable speed or suddenness.
[Middle English, gerund of lightnen, to illuminate, from lighten, from Old English līhtan; see leuk- in the Appendix of Indo-European roots.]