Someone who is competent is efficient and effective.
He was a loyal, distinguished, and very competent civil servant.
他是一个忠诚、出色、很有能力的公务员。
If you are competent to do something, you have the skills, abilities, or experience necessary to do it well.
Most adults do not feel competent to deal with a medical emergency involving a child.
多数成年人感到难以应付小孩医疗突发事件。