a person who works in a profession, especially medicine or law （尤指医学或法律界的）从业人员 dental practitioners 牙医 a qualified practitioner 合格执业者
a person who regularly does a particular activity, especially one that requires skill 习艺者；专门人才 one of the greatest practitioners of science fiction 最了不起的科幻小说家之一
Word Originmid 16th cent.: extension of obsolete practitian, variant of practician, from Old French practicien, from practique ‘practical’, via late Latin from Greek praktikos ‘concerned with action’, from prattein ‘do, act’.