Brief light show (5)
I believe the answer is:
flash
This clue might be a double definition.
'brief light' is the first definition.
'flash' can be an answer for 'light' (flash is a kind of light). I'm not sure about the 'brief' bit.
'show' is the second definition.
(flashing is a kind of showing)
Can you help me to learn more?
(Other definitions for flash that I've seen before include "Camera fitment" , "Momentary brightness" , "sort of flooding" , "Ostentatiously stylish" , "Ostentatious" .)