proficient

The company hired a proficient to improve its network security.

用法提示：这里 proficient 是名词，意为“专家”，指某个领域的行家。

She is known as a proficient in traditional Chinese calligraphy.

用法提示：proficient 作名词，表示在某方面很有造诣的专家。

The museum invited several proficients to authenticate the paintings.

用法提示：proficients 是 proficient 的复数形式，指多位专家。