When you make a mistake in your words as you are giving a speech, this is an example of when you stumble.
When you catch your foot on a crack in the sidewalk and almost fall down, this is an example of when you stumble.
The administration stumbled badly on foreign policy.
An example of a stumble is when you forget your line in a play.
To stumble through a speech.
To stumble across a clue.
Origin of stumble
- Middle English stumblen probably of Scandinavian origin Old Norse stumra
From American Heritage Dictionary of the English Language, 5th Edition