He is such a crumbum.

The park was filled with crumbums enjoying a picnic.

This is the crumbiest cake I've ever tasted.

This cake is crumbier than the last one.

I need to buy some crumblers for the recipe.

The crumbler broke into small pieces.

The cake had a crumblike texture.

She baked the cookies crumbily.

The crumbiness of the cake made it difficult to eat.

This crumbless cookie is perfect for those who don't like a mess.