Synonyms for improper

modified

1. Unsuitable

   unseemly, unbecoming, at odds, ill-advised, unsuited, indecorous, incongruous, out of place, ludicrous, incorrect, preposterous, unwarranted, undue, imprudent, unadapted, abnormal, irregular, inexpedient, unseasonable, inadvisable, untimely, inopportune, unfit, malapropos, unfitting, inappropriate, unapt, unbefitting, untoward, unmeet, ill-timed, awkward, inharmonious, discordant, discrepant, inapplicable, ill-assorted, odd; see also unsuitable.

2. Immoral

   indecent, indelicate, immodest, lewd, naughty, suggestive, smutty; see also lewd 1.

improper, the word of broadest application in this list, refers to anything that is not proper or suitable, esp. to that which does not conform to conventional standards; unseemly applies to that which is improper or inappropriate to the particular situation her unseemly laughter at the funeral; unbecoming applies to that which is inappropriate to a certain kind of person, his character, etc. his rigid views are most unbecoming in a teacher; indecorous refers to that which violates propriety or good taste in behavior, speech, etc. his indecorous interruption of their chat; indelicate implies a lack of propriety or tact and connotes immodesty or coarseness an indelicate anecdote; indecent is used of that which is regarded as highly offensive to morals or modesty indecent exposure