What does "out of line" mean?

Uncalled for, improper; inappropriate. For example, His remarks were totally out of line. It is often put as get out of line or step out of line, meaning “behave improperly,” as in She really stepped out of line when she called him incompetent in front of his boss. [Late 1700s]

Not in agreement with general practice, as in Their prices are way out of line with other hotels. Both def. 1 and 2 are metaphoric expressions that transfer being out of alignment to various kinds of behavior.

out of one's line; not in one's line. Not in one's occupation or field of interest. For example, He offered a generous salary, but the work was out of her line, or I'd love to help, but telephone solicitation is not in my line. This usage alludes to line in the sense of “a business or occupation.” [Mid-1800s]