Synonyms for Warning sign:

• n.

  •omen (noun)
  • sign of things to come.
  •sign of things to come (noun)
  • premonition,
  • warning,
  • prediction,
  • signal,
  • portent,
  • handwriting on the wall,
  • harbinger,
  • sign.

• Other synonyms:

  •Other relevant words:
  • trendy,
  • springy,
  • agile,
  • red light,
  • omen,
  • skull and crossbones,
  • skunk,
  • energetic,
  • fresher,
  • stormy petrel,
  • gathering clouds,
  • thundercloud,
  • precursor,
  • symptom,
  • red flag,
  • brisk,
  • spry,
  • monitor,
  • adroit.