stumble (n.) Look up stumble at Dictionary.com
1540s, "act of stumbling," from stumble (v.). Meaning "a failure, false step" is from 1640s.
stumble (v.) Look up stumble at Dictionary.com
c. 1300, "to trip or miss one's footing" (physically or morally), probably from a Scandinavian source (compare dialectal Norwegian stumla, Swedish stambla "to stumble"), probably from a variant of the Proto-Germanic base *stam-, source of Old English stamerian "to stammer," German stumm, Dutch stom "dumb, silent." Possibly influenced in form by stumpen "to stumble," but the -b- may be purely euphonious. Meaning "to come (upon) by chance" is attested from 1550s. Related: Stumbled; stumbling. Stumbling-block first recorded 1526 (Tindale), used in Romans xiv.13, where usually it translates Greek skandalon.