younger brother (polite, archaic)
Archaic polite term for one's own or someone else's younger brother. The suffix 君 (ぎみ) adds respect. In modern Japanese, 弟 (おとうと) is standard, and 弟さん (おとうとさん) is the common polite form.
In classical literature, scenes where a younger brother serves his elder brother are often depicted.
Compound of 弟 (おとうと, 'younger brother') and the honorific suffix 君 (ぎみ), an archaic reading of 君 used in respectful terms. The exact historical derivation is uncertain, but the form is attested in classical Japanese.