Which term describes someone who is sufficiently qualified and capable of performing tasks effectively?

The term that best describes someone who is sufficiently qualified and capable of performing tasks effectively is "competent." Being competent means that an individual possesses the necessary skills, knowledge, and experience to perform a specific job or task to an acceptable standard. This implies a level of proficiency and reliability in executing responsibilities, which is essential in any professional setting where effective performance is vital.

In contrast, the other terms highlight different levels of capability. "Incompetent" refers to someone lacking the necessary skills or qualifications, which directly opposes the definition of competence. "Amateur" typically indicates someone who is not a professional and may lack the experience or expertise associated with a qualified individual, often suggesting a lack of proficiency. "Inefficient" describes a person who may be capable but struggles to utilize their skills effectively or manage their time, leading to suboptimal performance. Thus, competence stands out as the term that accurately encapsulates sufficient qualification and effective task performance.