Lacking in both qualities of harmony or melody. Characteristic belonging to a person, group or venue (A.K.A. 'performance', 'concert', 'song', 'gig', 'rap', etc.), or the noise produced by said entity.
Like Angie Dickinson who merely tried to sing, William Shatner actually produced a recording of his singing that could best be described as aharmelodious. The resulting lack of sales and criticism are surprises only to those people who fail to hear their critics.
William Shatner, Grand Funk Railroad, Beach Boys, Ornette Coleman.