неважный

1) General subject: bad, baddish, fair to middling, immaterial, inconsiderable, indifferent, inessential, la la, nickel and dime, nickel-and-dimed, nickel-and-diming, nickeled-and-dimed, nickeling-and-diming, no great shakes, non-essential, not much of a..., not very good, of a kind, of no consequence, of no moment, omissible, one eyed, one horse, one-eyed, penny-ante, poor, slight, small, so-so, third-rate, this box will make a table of a kind, trifling, unimportant, of little moment, ropey, nonthreatening

2) Colloquial: tin

3) Rare: la-la

4) Mathematics: insignificant, irrelevant, not good

5) Jargon: Cheap John, back-burner, jerk soup, jerk town, jerk water, off base, mickey-mouse, peanut, penny ante

6) Makarov: none so good, nonessential, tenuous

7) Taboo: common as cat shit, half-assed

8) Phraseological unit: not worth a pinch of coon's shit (only CANADIAN, not to be used in USA (coon in USA is a slang for a coloured man))