A more thorough explanation:

Definition: A deviation or divergence from a standard rule, regulation, measurement, or course of conduct.

Example: An impermissible departure from sentencing guidelines.

This means that when a court does not follow the standard guidelines for sentencing a criminal, it is considered a departure. For example, if the court gives a more lenient sentence than what the guidelines suggest, it is called a downward departure. On the other hand, if the court gives a harsher sentence than what the guidelines suggest, it is called an upward departure.

Example: A variance between a pleading and a later pleading or proof.

This means that when there is a difference between what someone initially claimed in a legal case and what they later prove, it is called a departure. For example, if a plaintiff claims one thing in their initial pleading but later proves something different, it is considered a departure.

Example: A party's desertion of the ground taken in the immediately preceding pleading and resort to another ground.

This means that when someone changes their argument in a legal case, it is considered a departure. For example, if a defendant initially claims they have an alibi for a crime but later changes their argument and pleads guilty, it is considered a departure.