古灵精怪

古靈精怪
gǔlíngjīngguài
(idiom) mischievously clever; whimsically quirky

CEDICT

weird; bizarre

Wiktionary

形容人慧黠而精明。

重編國語辭典

Entry Composition

1 古 gǔ
  1. ancient
  2. old
  3. paleo-
2 灵 líng
  1. quick
  2. alert
  3. efficacious
  4. effective
  5. to come true
  6. spirit
  7. departed soul
  8. coffin
3 精怪 jīngguài supernatural being (such as a demon, monster, ghost, spirit, gremlin etc)