Lack of professional ability, in other words.

Insufficient business ability, limited business level and poor business ability.

1. Lack of business ability: refers to a person who is engaged in a specific business field or task and cannot effectively complete the work due to lack of necessary skills, knowledge or experience.

2. Limited business level: refers to a person's business ability and level does not reach the expected standard or level, and there is a certain gap in skills, knowledge or experience.

3. Poor business ability: It means that a person's business ability and performance do not reach a good standard, which is caused by unskilled skills, incomplete knowledge or insufficient experience.