Other forms: durably
Something that is built to last is durable. Your most durable pair of hiking boots will last you through your trek to the summit of Mount Everest.
Anything that's long-lasting, sturdy, or doesn't bend under pressure can be described as durable. You could have a durable relationship with your oldest friend, durable tires on your car, and a durable umbrella — they won't let you down or break. The Latin root of durable is durabilis, which means "lasting or permanent," and comes from durare, "to harden."