ぐ【御】 : gu | define meaning

Cognate with the standard Japanese honorific prefix ご【御】 go.

Historical Ryukyuan attestations

• Essay in Aid of a Grammar and Dictionary of the Luchuan Language (1895), by Basil Hall Chamberlain, records "The prefuxes u, gu and mi, which signify literally 'honourable' or 'august,' are almost always preferred to the personal pronouns in addressing a superior or even an equal. Thus u byō-chi, 'your illness;' mi fisha, 'your leg' (...)".
• 沖縄語典 Okinawa goten (Okinawan language dictionary) (1896), by Masayo Nakamoto, records "「ぐじん」御前（ゴゼン）、貴人ノ座前ノ敬語", "「ぐ𛃥う」御用（ゴヨウ）", "「ぐらん」御覧（ゴラン）", "「ぐみん、う𛀁んみさ」御免（ゴメン）", "「ぐむつィ」御物（ゴモツ）、皇室又ハ御蔵所ノ物", and "「ぐひい、うんもーし」御弊（ゴヘイ）", among other examples.