1flash 
/ˈflæʃ/ verb
flash·es; flashed; flash·ing /ˈflæʃ/ verb 1 : to shine or give off bright light suddenly or in repeated bursts [no obj] ▪ Thunder rumbled and lightning flashed. ▪ Cameras flashed as the celebrities passed. ▪ A car was sitting on the side of the road with its lights flashing. [+ obj] ▪ She flashed her car's headlights (at us) and honked her horn. 2 a : to appear quickly or suddenly [no obj] ▪ A message flashed on the screen. [+ obj] ▪ The screen flashed a message in black letters.
b [no obj] : to move or pass very quickly
▪ A car flashed by. ▪ An idea flashed into/through his mind. [=he suddenly had an idea] 3 [no obj] of the eyes : to show strong emotion
▪ Her eyes flashed with anger. 4 [+ obj] : to show (something) briefly
▪ The mugger flashed a knife and demanded their wallets. ▪ The officer flashed his badge. ▪ She flashed a shy smile. 5 informal : to show your sexual organs to (someone) suddenly and briefly in public [+ obj] ▪ A strange man flashed her on the subway. [no obj] ▪ He was arrested for flashing. — see also flasher
b [no obj] : to move or pass very quickly
▪ A car flashed by. ▪ An idea flashed into/through his mind. [=he suddenly had an idea]
▪ Her eyes flashed with anger.
▪ The mugger flashed a knife and demanded their wallets. ▪ The officer flashed his badge. ▪ She flashed a shy smile.
