WordWeb Online

1. Not important
   "a relatively unimportant feature of the system"; "the question seems unimportant"
    
2. Devoid of importance, meaning, or force
   - insignificant

See also: fiddling [informal], flimsy, footling [informal], fragile, hole-and-corner, hole-in-corner, immaterial, importance, inappreciable, inconsequent, inconsequential, indifferent, inessential, light, lightweight, lilliputian [informal], little [informal], meaningless, nickel-and-dime [N. Amer, informal], niggling [informal], niggly [informal], nonmeaningful, petty [informal], picayune [N. Amer, informal], piddling [informal], piddly [informal], piffling [informal], potty [Brit, informal], rinky-dink [N. Amer, informal], significance, slight, small-time, superficial, tenuous, thin, trivial, unessential

Antonym: of import