If you can tolerate something, it's endurable. Getting a cavity filled at the dentist, while not very fun, is still endurable.
Use the adjective endurable to describe something that's no fun, but that a person can generally deal with. Standardized tests are endurable, and eating soggy, overcooked broccoli is endurable. A long ride on a stormy sea — as long as the ship doesn't capsize — is also endurable. To endure something is to withstand it — if it's endurable, it can be endured. The word is rooted in the Latin indurare, "to make hard or firm."