The adjective accomplished is useful for describing someone who's very good at something. You might use it to talk about yourself if you are an accomplished — or highly skilled — sword swallower.
An accomplished ice skater is someone who can do one of those fancy twirls on the ice, and an accomplished cupcake baker is someone you want to be friends with. Another way to use the word accomplished is to mean "successfully completed or finished." You might say, "I accomplished my goal of climbing the highest mountain east of the Mississippi River." Next up: Everest.