What is the meaning of foundering?

noun

• Of a ship. ( sinking)
  • synonyms: going under

verb

• Fail utterly; collapse.
  • usage: "The project foundered"
  • synonyms: fall through, fall flat, founder, flop
• Sink below the surface.
  • synonyms: founder
• Break down, literally or metaphorically.
  • usage: "The wall collapsed"; "The business collapsed"; "The dam broke"; "The roof collapsed"; "The wall gave in"; "The roof finally gave under the weight of the ice"
  • synonyms: collapse, fall in, cave in, give, give way, break, founder
• Stumble and nearly fall.
  • usage: "the horses foundered"
  • synonyms: founder