accessory

(noun) clothing that is worn or carried, but not part of your main clothing. Synonyms: accoutrement, accouterment.

(noun) a supplementary component that improves capability. Synonyms: appurtenance, supplement, add-on.

(noun) someone who helps another person commit a crime. Synonyms: accessary.

(adj) aiding and abetting in a crime. Synonyms: accessary. Example: "He was charged with being accessory to the crime."

(adj) furnishing added support. Synonyms: adjunct, ancillary, adjuvant, appurtenant, auxiliary. Examples: "An ancillary pump." "An adjuvant discipline to forms of mysticism." "The mind and emotions are auxiliary to each other."