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stumble v. stumbled, stumbling, stumbles v.intr.
1.To miss one's step in walking or running; trip and almost fall.
2.To proceed unsteadily or falteringly; flounder. See Synonyms at blunder.
3.To act or speak falteringly or clumsily.
4.To make a mistake; blunder.
5.To fall into evil ways; err.
6.To come upon accidentally or unexpectedly.