医師|いしishi[1]atamadaka (head-high)

1. noundoctor; physician
   あの紳士しんしは医師いしにちがいない。↗

   That gentleman must be a doctor.

• SynonymドクターNeutralA loanword for doctor, but it also means a PhD or doctorate; as a form of address it is fairly casual, while 「医師」 is the formal professional title.
• Synonymお医者さんおいしゃさんCasualA warm, polite way to refer to a doctor, used mostly in conversation and when talking to children; 「医師」 is the formal term for documents.
• Synonym医者いしゃNeutralThe everyday word for a doctor, as in 「医者に行く」; 「医師」 is the formal legal and professional designation used in news and on official documents.
• Antonym患者かんじゃNeutralThe person who receives treatment; in the medical relationship 「患者」 is the counterpart standing opposite 「医師」.

In everyday speech say 「医者」; use 「お医者さん」 for a friendly, polite tone. 「医師」 is the formal professional term for official documents and news; 「ドクター」 also covers PhDs. 「患者」 is the patient, the doctor's counterpart.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. けがや病気びょうきの治療ちりょう、または病気びょうきの予防よぼうにあたる職業しょくぎょう。現在げんざいの日本にっぽんでは、医師法いしほうに基もとづいて医療いりょう行為こういをおこなう資格しかくを有ゆうする者もの。