Synonyms for Be on the horizon:

• v.

  •threaten (verb)
  • portend,
  • warn,
  • hang over,
  • approach,
  • impend,
  • be in the air,
  • put at risk,
  • put in jeopardy,
  • come on,
  • jeopardize,
  • forebode,
  • brewing,
  • be dangerous,
  • foreshadow,
  • loom,
  • advance,
  • be imminent,
  • frighten,
  • overhang,
  • be gathering,
  • presage,
  • imperil,
  • be in the offing.

• Other synonyms:

  •endanger
  • threaten.
  •threaten
  • hanging over.

Antonyms for Be on the horizon:

• v.

  • threaten
    protect, relieve, alleviate, save, help, guard.