impertinent

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adjective Exceeding the limits of propriety or good manners; improperly forward or bold.
• adjective Not pertinent: synonym: irrelevant.

from The Century Dictionary.

• Not pertinent; not pertaining to the matter in hand; not to the point; irrelevant; inapposite; out of place.
• Negligent of or inattentive to the matter in hand; careless; frivolous.
• Contrary to the rules of propriety or good breeding; uncivil: speaking or acting presumptuously or offensively; pragmatical; meddling: as, impertinent behavior; an impertinent boy.
• Synonyms Impertinent, Officious, saucy, impudent, insolent, rude, unmannerly, pert, bold, Impertinent means forward, intrusive, generally from curiosity, but sometimes with undesired advice, etc.; officious means forward to offer and undertake service where it is neither needed nor desired. A busybody may be either impertinent or officious, or both. See impudence.
• noun One who interferes in what does not concern him; one who is rude, uncivil, or offensive in behavior; a meddler; an intruder.

from the GNU version of the Collaborative International Dictionary of English.

• adjective Not pertinent; not pertaining to the matter in hand; having no bearing on the subject; not to the point; irrelevant; inapplicable.
• adjective Contrary to, or offending against, the rules of propriety or good breeding; guilty of, or prone to, rude, unbecoming, or uncivil words or actions
• adjective Trifing; inattentive; frivolous.
• noun rare An impertinent person.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective insolent, ill-mannered
• adjective irrelevant (opposite of pertinent)

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• adjective characterized by a lightly pert and exuberant quality
• adjective improperly forward or bold
• adjective not pertinent to the matter under consideration