* Verb (past participle): This is the most common usage, meaning "to carry out or put into effect," or in a more extreme sense, "to kill by official order." Example: "The plan was executed flawlessly." or "The prisoner was executed at dawn."
* Adjective: This usage is less common, meaning "having been carried out or completed," or in the case of a piece of art, "having been performed well." Example: "The executed design was stunning." or "The pianist gave an executed performance."
To determine the correct part of speech, you need to look at the context of the sentence.