Lumpy describes something covered with bumps or uneven chunks instead of being smooth. When you make pudding and don't stir it well enough, it turns out lumpy with little clumps throughout. A lumpy mattress has uncomfortable bumps and dips that make it hard to sleep. Lumpy mashed potatoes have chunks of potato that didn't get mashed properly.

The word often suggests something went wrong in the making. A lumpy sweater might have thick spots where the knitting got tangled. Lumpy oatmeal means someone didn't mix it quite right. Lumpy gravy has flour clumps floating in it instead of being silky smooth.

Sometimes lumpy just describes natural bumpiness. A toad's skin is lumpy. Old tree bark looks lumpy and rough. After you fall and get a bruise, you might notice a lumpy swelling where you got hurt.

The opposite of lumpy is smooth or even. When you're cooking something that should be creamy, like cake batter or hot chocolate, you keep stirring until it's no longer lumpy. Getting rid of lumps usually takes patience and effort, whether you're mixing ingredients, fluffing a pillow, or smoothing out clay.