1. past tense of stumble: to trip or lose one’s balance while walking or running
2. past tense of stumble: to discover or encounter something unexpectedly
Usage: often followed by ‘upon’ or ‘across’
3. past tense of stumble: to make mistakes or speak hesitantly

Examples

• She stumbled on the uneven sidewalk and nearly fell.
• He stumbled over his words during the presentation.
• They stumbled upon an old treasure chest in the attic.
• The hiker stumbled down the rocky path in the dark.
• I stumbled across this interesting article while browsing online.
• The actor stumbled through his lines on opening night.
• We stumbled into the wrong classroom by mistake.