Acceptable means meeting the minimum standards or requirements for something, or being good enough to be approved or allowed. When your teacher says your homework is acceptable, it means the work meets the basic expectations, even if it's not outstanding. When behavior is acceptable, it follows the rules and doesn't cause problems.

The word sits in an interesting middle ground. Acceptable work isn't necessarily excellent or impressive: it simply clears the bar of what's needed. If a restaurant serves acceptable food, the meal won't make you sick and tastes fine, but you probably won't rush back to eat there again. If your parents say your room is in acceptable condition, they mean it's clean enough that they won't make you redo it, even if it's not spotless.

Sometimes people use acceptable when they're being diplomatic. Saying something is “barely acceptable” suggests it just squeaked by the minimum requirements. But acceptable can also carry real approval: when a scientist's research methods are acceptable to other experts, that's meaningful recognition that the work was done properly.

What's considered acceptable varies by situation and who's judging. Acceptable manners at a family picnic differ from acceptable manners at a formal dinner. Acceptable noise levels in a gymnasium are very different from acceptable noise levels in a library.