adjunct

nouns

something added to another thing but not an essential part of it
is a type of (narrower)
anything that is not essential
"they discarded all their inessentials"
a person who is an assistant or subordinate to another
is a type of (narrower)
a person who joins with others in some activity or endeavor
"he had to consult his associate before continuing"
a construction that can be used to extend the meaning of a word or phrase but is not one of the main constituents of a sentence
is a type of (narrower)
a group of words that form a constituent of a sentence and are considered as a single unit
"I concluded from his awkward constructions that he was a foreigner"

adjectives

furnishing added support
"an ancillary pump"; "an adjuvant discipline to forms of mysticism"; "The mind and emotions are auxiliary to each other"
of or relating to a person who is subordinate to another