stumble
noun.
an unsteady uneven gait
Synonym: lurch, stagger
noun.
an unintentional but embarrassing blunder
he recited the whole poem without a single trip|he arranged his robes to avoid a trip-up later|confusion caused his unfortunate misstep
Synonym: misstep, trip, trip-up
verb.
walk unsteadily
The drunk man stumbled about
Synonym: bumble, falter
verb.
miss a step and fall or nearly fall
She stumbled over the tree root
Synonym: trip
verb.
encounter by chance
I stumbled across a long-lost cousin last night in a restaurant
Synonym: hit
verb.
make an error
She slipped up and revealed the name
Synonym: trip up, slip up