What is the meaning of stumble?

noun

• An unsteady uneven gait.
  • synonyms: lurch, stagger
• An unintentional but embarrassing blunder.
  • usage: "he recited the whole poem without a single trip"; "he arranged his robes to avoid a trip-up later"; "confusion caused his unfortunate misstep"
  • synonyms: trip, trip-up, misstep

verb

• Walk unsteadily.
  • usage: "The drunk man stumbled about"
  • synonyms: falter, bumble
• Miss a step and fall or nearly fall.
  • usage: "She stumbled over the tree root"
  • synonyms: trip
• Encounter by chance.
  • usage: "I stumbled across a long-lost cousin last night in a restaurant"
  • synonyms: hit
• Make an error.
  • usage: "She slipped up and revealed the name"
  • synonyms: slip up, trip up