Wiktionary
vb. 1 (context figuratively English) To discover or find something by accident. 2 (context figuratively English) To meet somebody by chance.
Usage examples of "stumble against".
He heard the farmer stumble against the door and mutter, but he could not attend to it.
Any number of camels, either from accident or from being half-crazed by wounds, did stumble against the pikes.
She hardened her resolve and stole along at the rear of the little column, trying to pick up her feet and put them down as silently as the Amazons, not to stumble against a chance stone.
A well-timed stumble against a modestly dressed, middle-aged woman .
They know all the furniture in the dark, but me, I stumble against every chair and end table.
Just stand close to the top of the gangplank and I will stumble against you.