WordNet sense 1 (of superficial relevance if any):

tangential

WordNet sense 2 (having no bearing on or connection with the subject at issue):

irrelevant

WordNet sense 3 ((of e.g. speech and writing) tending to depart from the main point or cover a wide range of subjects):

discursive, excursive, rambling

WordNet sense 4 (extended senses; not direct in manner or language or behavior or action):

indirect