stumble stumble /ˈstʌmbəl/

noun

1. An unintentional but embarrassing blunder  ( misstep , stumble , trip , trip-up )
   an unintentional but embarrassing blunder
    He recited the whole poem without a single trip
   he recited the whole poem without a single trip
    He arranged his robes to avoid a trip-up later
   he arranged his robes to avoid a trip-up later
    Confusion caused his unfortunate misstep
   confusion caused his unfortunate misstep
   
2. An unsteady uneven gait  ( stagger , stumble , lurch )
   an unsteady uneven gait
   

verb

1. () Walk unsteadily  ( bumble , falter , stumble )
   walk unsteadily
    The drunk man stumbled about
   The drunk man stumbled about
   
2. () Miss a step and fall or nearly fall  ( trip , stumble )
   miss a step and fall or nearly fall
    She stumbled over the tree root
   She stumbled over the tree root
   
3. () Encounter by chance  ( stumble , hit )
   encounter by chance
    I stumbled across a long-lost cousin last night in a restaurant
   I stumbled across a long-lost cousin last night in a restaurant
   
4. Make an error  ( slip up [Informal] , stumble , trip up )
   make an error
    She slipped up and revealed the name
   She slipped up and revealed the name