The antonyms for the phrase "having know-how" are "ignorant," "inexperienced," and "clueless." These words describe individuals who lack the necessary knowledge and skills to perform a particular task or job. Ignorant refers to those who are unaware of certain information or are uneducated about a topic. Inexperienced implies a lack of practice, training, or exposure to a particular field or job. Lastly, clueless suggests incompetence, naivety, or a lack of understanding. Overall, the antonyms for "having know-how" describe those who are not adept or proficient in a specific area, highlighting the importance of continuous learning and personal development.