flash a smile

flash (one) a smile

To smile at one, usually quickly and perhaps unexpectedly. She was sad this morning, but I think she's feeling better now—she flashed me a smile before she left.
See also: flash, smile
Farlex Dictionary of Idioms.

flash a smile (at someone)

Fig. to smile quickly and perhaps briefly at someone. She flashed a smile at me as if she recognized me.
See also: flash, smile
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • a mystery to (one)
  • appear to
  • be in low spirits
  • a change of heart
  • a shoulder to cry on
  • a yellow streak
  • a turn of phrase
  • able to do
  • able to do it
  • a tough customer/cookie
References in periodicals archive
Here's a new way to flash a smile: Waft a glowing plasma of charged particles onto your teeth.
Radiant plasma may combat cavities
Pretend you just noticed him right before you reach him, then catch his gaze and flash a smile as you pass.
The secret language of like: sneaky ways to let your crush know you pig him--without saying a word!