disrespectful

Having or exhibiting a lack of respect; rude and discourteous.

adjective

1. Having or showing a lack of respect: irreverent. See respect/contempt/standing.
2. Lacking good manners: discourteous, ill-bred, ill-mannered, impolite, rude, uncivil, ungracious, unmannerly, unpolished. See courtesy/discourtesy.

Definition: insulting, rude
Antonyms: civil, courteous, mannered, mannerly, nice, respectful

The adjective has 2 meanings:

Meaning #1: exhibiting lack of respect; rude and discourteous
  Antonym: respectful (meaning #1)

Meaning #2: neither feeling nor showing respect
  Synonyms: aweless, awless