Detailed description and alternate definitions of the word 'accessory':

One who aids a criminal after the commission of a crime, but was not present at the time of the crime. Also called

Having a secondary, supplementary, or subordinate function.

A subordinate or supplementary item; an adjunct.

One who incites, aids, or abets a lawbreaker in the commission of a crime but is not present at the time of the crime. Also called

Something nonessential but desirable that contributes to an effect or result.

Serving to aid or abet a lawbreaker, either before or after the commission of the crime, without being present at the time the crime was committed.
Synonyms of word 'accessory' :

accessary

appurtenant

supplement

add-on

ancillary

adjunct

accessary

adjuvant

appurtenance

auxiliary

accouterment

accoutrement