accessory

nouns

clothing that is worn or carried, but not part of your main clothing
accessory, accouterment, accoutrement
is derived from
accessorial
a supplementary component that improves capability
accessory, add-on, appurtenance, supplement
is derived from
accessorial
someone who helps another person commit a crime
accessary, accessory

adjectives

aiding and abetting in a crime
"he was charged with being accessory to the crime"
accessary, accessory
furnishing added support
"an ancillary pump"; "an adjuvant discipline to forms of mysticism"; "The mind and emotions are auxiliary to each other"
accessory, adjunct, adjuvant, ancillary, appurtenant, auxiliary