The noun worth refers to the monetary value of something. If your grandmother gives you a strange old coin from her collection, you can have it appraised to determine its worth.
The noun worth also means the inherent value of something based on the qualities of excellence, usefulness or importance. Don't underestimate your worth to the group; the whole bake sale would have fallen apart without you, and your brownies were delicious. As an adjective worth describes something that has a value or deserves to be treated a certain way, like when your hard work baking is worth the effort.