extraneous

not pertinent to the matter under consideration

• “an issue extraneous to the debate”
• “the price was immaterial”
• “mentioned several impertinent facts before finally coming to the point”

not essential

• “the ballet struck me as extraneous and somewhat out of keeping with the rest of the play”

not belonging to that in which it is contained; introduced from an outside source

• “water free of extraneous matter”
• “foreign particles in milk”

coming from the outside

• “extraneous light in the camera spoiled the photograph”
• “relying upon an extraneous income”
• “disdaining outside pressure groups”