If something is excessive, it is too much, or more than it should be.

Example uses:

His excessive drinking finally killed him.

I called the police on my neighbor because of excessive noise.

Your excessive usage of profanity really turns people off.

It’s ok that you pointed out some areas where he could improve, but you went too far and criticized him too much. It was excessive.

Similar ways to express the same meaning:

Overkill

Extreme

Overboard