患者
かんじゃ · kanja · JLPT N3 · noun
patient
🏥🤒 患者 = suffer + person: the one with the ailment
患 means affliction or worry, the same 患 as in 疾患 (disease). 者 means person, as in 医者 (doctor). So the doctor is the medicine-person and the patient is the suffering-person, and the two words share their second kanji.
患 — 串 chuàn (phonetic) + 心 heart
A semantic-phonetic compound: 心 'heart/mind' gives the meaning of inner worry, while 串 'string/skewer' suggests the sound. The original sense was anxiety or troubles weighing on the mind, which later extended to 'suffer from' an illness or calamity.
者 — old/elder 耂 + say 曰
Originally depicted sugarcane or a similar plant, but the form was reanalyzed as 耂 (old) over 曰 (say). It became a grammatical suffix meaning 'one who…' or 'the…thing,' nominalizing verbs and adjectives. Today 者 mainly marks agents or categories, as in 学者 'scholar' or 记者 'reporter.'