Articulacy is the ability to express oneself fluently and coherently in words. Antonyms for this word would include inarticulacy, which means a lack of ability to communicate effectively, stammering or hesitancy while speaking. People who are inarticulate find it difficult to express their thoughts and feelings clearly. Another antonym for articulacy is unintelligible, which refers to speech that is hard to comprehend, mumbled or slurred. In contrast to articulacy, both inarticulacy and unintelligibility can have negative connotations and may indicate a lack of confidence or education.