1. breaks or falls apart into small pieces
Usage: third person singular present
2. gradually weakens and fails
Usage: third person singular present; figurative

1. a baked dessert with fruit and a crumbly topping
Usage: plural

Examples

• The old wall crumbles when you touch it.
• Her confidence crumbles under pressure.
• The cookie crumbles into tiny pieces.
• Their marriage crumbles after years of problems.
• She makes delicious apple crumbles for dessert.
• The ancient building crumbles with age.
• His alibi crumbles when questioned closely.
• We ordered two fruit crumbles at the restaurant.