Noah Webster
Behavior
BEHA'VIOR, noun behavyur. [See Behave.]
Manner of behaving, whether good or bad; conduct; manners; carriage of one's self, with respect to propriety, or morals; deportment. It expresses external appearance or action; sometimes in a particular character; more generally in the common duties of life; as, our future destiny depends on our behavior in this life. It may express correct or good manners, but I doubt whether it ever expresses the idea of elegance of manners, without another word to qualify it.
To be upon one's behavior is to be in a state of trial, in which something important depends on propriety of conduct. The modern phrase is, to be or to be put, upon one's good behavior