additional — Additional things are extra things apart from the ones already present.
auxiliary — An auxiliary is a person who is employed to assist other people in their work. Auxiliaries are often medical workers or members of the armed forces.
extra — Added to an existing or usual amount or number.
inessential — not essential; not necessary; nonessential.
insignificant — unimportant, trifling, or petty: Omit the insignificant details.
minor — lesser, as in size, extent, or importance, or being or noting the lesser of two: a minor share.
nonessential — not essential; not necessary: Nonessential use of gasoline was forbidden during the war.
secondary — next after the first in order, place, time, etc.
trivial — of very little importance or value; insignificant: Don't bother me with trivial matters.
unimportant — of much or great significance or consequence: an important event in world history.
unsubstantial — not substantial; having no foundation in fact; fanciful; insubstantial: an unsubstantial argument; unsubstantial hopes.
exterior — Forming, situated on, or relating to the outside of something.
extreme — Reaching a high or the highest degree; very great.
inferior — lower in station, rank, degree, or grade (often followed by to): a rank inferior to colonel.
outer — situated on or toward the outside; external; exterior: outer garments; an outer wall.
outside — the outer side, surface, or part; exterior: The outside of the house needs painting.
subordinate — placed in or belonging to a lower order or rank.
peripheral — pertaining to, situated in, or constituting the periphery: peripheral resistance on the outskirts of the battle area.
