The antonyms for the phrase "art able to" include "not capable of," "incompetent," "inept," "unable," and "incapable." These words negate the ability or talent suggested by the phrase "art able to." In other words, they indicate that someone or something lacks the skill, knowledge or resources to perform a task or create something of value. It's important to note that these words should be used with care, especially when referring to individuals, as they can be perceived as judgmental or insulting. Instead, it's often preferable to use more neutral language that focuses on the specific skills or qualities that are needed for a task, and areas where the person or thing could improve.