The difference between Boo-boo and Stumble

When used as nouns, boo-boo means a mistake or error, whereas stumble means a fall, trip or substantial misstep.

When used as verbs, boo-boo means to defecate, whereas stumble means to trip or fall.

check bellow for the other definitions of Boo-boo and Stumble

Boo-boo as a noun (countable, colloquial, often, childish):

A mistake or error.
Boo-boo as a noun (countable, colloquial, childish, by or to young children):

A minor injury, such as a cut or a bruise.
Boo-boo as a noun (uncountable, colloquial, childish, by or to young children):

Feces.

Boo-boo as a verb (colloquial, childish, by or to young children):

To defecate.

Stumble as a verb (intransitive):

To trip or fall; to walk clumsily.

Examples:

"He stumbled over a rock."
Stumble as a verb (intransitive):

To make a mistake or have trouble.

Examples:

"I always stumble over verbs in Spanish."
Stumble as a verb (transitive):

To cause to stumble or trip.
Stumble as a verb (transitive, figurative):

To mislead; to confound; to cause to err or to fall.
Stumble as a verb:

To strike or happen (upon a person or thing) without design; to fall or light by chance; with on, upon, or against.