a person who is qualified to work in a profession, especially medicine or law （尤指医学或法律界的）从业人员◆a medical/legal practitioner 开业医生／律师◆the Institute of Practitioners in Advertising 广告从业者协会
a person who regularly does a particular activity or follows a particular theory 专门人才◆enthusiastic practitioners of lean manufacturing 热衷於精益制造的专家