The word "crumbier" means something that is more prone to crumbling or breaking apart into small pieces. Its antonyms, on the other hand, are words that mean the opposite of crumbly or brittle. They include terms like solid, firm, sturdy, robust, durable, strong, hard, tough, and unyielding. These words are often used to describe materials that are resistant to breaking or bending, such as concrete, steel, or wood. Alternatively, they can describe foods that are dense and substantial, like bread, meat, or cheese. By using these antonyms, you can convey the opposite of fragility or weakness, and emphasize strength, durability, and resilience.