The suffix -able (or sometimes -ible) attaches to the end of words to mean “capable of being” or “worthy of being” whatever the root word describes. When you add -able to a verb, you create an adjective that describes whether something can have that action done to it.

A readable book is one that can be read easily. A washable jacket can go in the washing machine without being ruined. Something breakable can be broken, so you need to handle it carefully. If your little brother's behavior is tolerable, that means you can tolerate it (at least for now).

Sometimes -able means “tending to” rather than “capable of being.” A likable person is someone who tends to be liked by others. A reasonable request is one that makes sense and seems fair.

The spelling sometimes changes to -ible for certain words (like terrible or edible). There's no simple rule for knowing which spelling to use, so when you're unsure, check a dictionary.

When you understand -able, you can often figure out new words you've never seen before. If someone describes a new discovery as verifiable, you can guess it means “capable of being verified” or proven true.