冴える

Meaning

1. v1vi
   to be clear (of a sight, sound, colour, etc.); to be bright; to be vivid; to be crisp
2. v1vi
   to be clear-headed; to be alert; to be on the ball; to be wide awake
3. v1vi
   to look upbeat; to be perky; to be cheerful
4. v1vi
   to master (a skill); to excel at; to cleanly execute
5. v1vi
   to be satisfying
6. v1vi
   to become frigid; to become intensely cold

Example sentences

• 昨日ゆっくり休んだ分、今日は頭が冴えている。

  I feel smart today, to a degree that is in proportion to the amount of good rest I had yesterday.

• なんだか目が冴えちゃって、眠れなくなっちゃった。

  For some reason, I'm wide awake and can't fall asleep.

• もう午前3時だけど、目が冴えて眠れる気がしない。

  It's already 3 a.m., but I'm wide awake and couldn't fall asleep if I tried.