on or related to the side of the body which in most people has the more skilful hand, or to the side of a person or thing which is toward the east when that person or thing is facing north (opposite to left)
It is quite difficult to be a friend to someone who is very {moody}.
If you describe someone as moody, you mean that their feelings and behaviour change frequently, and in particular that they often become depressed or angry without any warning.
It is quite difficult to be a friend to someone who is very {moody}.