Extraneous which comes from the Latin term extraneus (related to strange in English; extraño in Spanish), means irrelevant or nonessential.
- Extravagant means beyond what is reasonable or appropriate, as in going beyond in cost or decoration, for example.
- Extrinsic, from a Latin word meaning from without, is a synonym of extraneous.
Superfluous, which comes from Latin and literally means overflowing, means extra, more than is necessary.
- Supererogatory is usually used in regards to done beyond what is required.
- Supernumerary means exceeding the usual or more numerous. It is also used in noun form to refer to an extra person, especially in theater as a formal equivalent of the film term extra.
- Redundant has the same literal meaning as superfluous and also refers to repetition, abundance, extravagance, or duplication.
- More common (and easier to pronounce) synonyms include: excess, spare, and surplus.