Adjective

1. Responsible for a dishonest act.

   He was guilty of cheating at cards.

2. Judged to have committed a crime.

   The guilty man was led away.

3. Having a sense of guilt

   Do you have a guilty conscience?

4. Blameworthy.

   I have a guilty secret.

Noun

1. A plea by a defendant who does not contest a charge.
2. A verdict of a judge or jury on a defendant judged to have committed a crime.