When you do something ineffectually, you try, but you do not have the skill, confidence, or authority to make it work. The effort is there; the power is not. People may talk over you. The door stays shut. We often use it of someone who is in the role but cannot take charge — a weak chair of a meeting, a shy teacher trying to quiet a class. It is a little formal, and it can sound unkind if you aim it at a person. Though actually, because this is the -ly form, it describes the way the trying looks, not a label stuck on the person. You will also hear it of a small action that goes nowhere: knocking ineffectually on a heavy door. Same picture: busy hands, no result.

無力地、沒有魄力地（偏「使不上力、鎮不住場」；不要只記成「無效地」）