Synonyms for Unimportant:

adj.

all (adjective)
insignificant.
humble (adjective)
low-ranking.
immaterial (adjective)
of no account, of no consequence.
inconsiderable (adjective)
inconsiderable.
little (adjective)
inconsequent.
of no real worth, value (adjective)
little, irrelevant, beside the point, immaterial, paltry, picayune, unnecessary, petty, negligible, indifferent, of no consequence, slight, inconsequential, worthless, inconsiderable, low-ranking, trivial, second-rate, minute, trifling, frivolous, insignificant, of no account.
small (adjective)
paltry.
unimportant (adjective)
insipid, banal, insignificant, measly, Flyspeck, irrelevant, fiddling, trite, trifling, negligible, worthless, minute, frivolous, trivial, one-horse, inconsequential, piddling.

n.

neither here nor there, academic, unrelated, inappropriate, extraneous, marginal. trifling (noun)
penny ante, negligible, inconsiderable, paltry, unnecessary, slight, of no moment, of no consequence, of no account, second-rate, low-ranking, beside the point.
unimportant (noun)
small-time, hole-and-corner, inconsequential, little, nickel-and-dime, fiddling, trivial, petty, niggling, lilliputian, hole-in-corner, piddling, inconsequent, mickey mouse, indifferent, light, potty, immaterial, inappreciable, piffling, lightweight, footling, superficial, picayune.

Other synonyms:

Mickey Mouse
mickey mouse.
marginal, unrelated, extraneous. academic, light. negligible
inconsiderable.
trifling
penny ante, slight.
Other relevant words:
light, hole-in-corner, inconsiderable, inappreciable, beside the point, indifferent, footling, mickey mouse, of no consequence, second-rate, penny ante, of no moment, picayune, piffling, inappropriate, unnecessary, paltry, unrelated, little, small-time, immaterial, petty, lilliputian, inconsequent, slight, superficial, extraneous, marginal, potty, lightweight, academic, neither here nor there, nickel-and-dime, negligible, of no account, niggling, hole-and-corner.

Usage examples for unimportant

  1. " You are certainly unimportant she agreed. – The Iron Woman by Margaret Deland
  2. That's the tragic thing about money- that it is both so important and so unimportant – Father Payne by Arthur Christopher Benson