1. Literally, to not be correctly positioned in a line with other people or things. Adjust that frame on the left—it's out of line with the other pictures on the wall. I was only out of line for a minute! Can't you let me back in?

2. To act in an inappropriate or unacceptable way. That reporter was out of line when he asked questions about my personal life. I'm sorry about last night, I was out of line when I made those demands.

3. To be inconsistent (with something else). That car service's exorbitant rates are out of line with others in the industry.

4. To be outside of one's skills or interests. In this usage, a noun or pronoun is used between "in" and "line." My brother is really studious, so sports are out of his line, as they interfere with his studying.