stumbler

intransitive verb stumbled, stumbling

1. to trip or miss one's step in walking, running, etc.
2. to walk or go in an unsteady or awkward manner, as from age, weakness, etc.
3. to speak, act, or proceed in a confused, blundering manner: to stumble through a speech
4. to fall into sin or error; do wrong
5. to come by chance; happen: to stumble across a clue

Origin: ME stumblen < Scand, as in Norw dial. stumba, ON stumra < IE base *stem-, to bump against, hamper > stammer, Ger stumm, Du stom, mute

transitive verb

1. to cause to stumble
2. to puzzle or perplex; confound

noun

1. the act of stumbling
2. a blunder, error, or sin