accessory
ac-ces-so-ry
noun
An item enhancing an outfit or device, not strictly essential.
"She chose a matching handbag as the perfect accessory."
noun
A person who assists another in committing a crime.
"He was charged as an accessory to the robbery."
Thesaurus
Synonyms: supplement, add-on, appurtenance, appurtenant, adjunct, adjuvant, ancillary, supportive, auxiliary, accouterment, accoutrement, accessary