大口 おおぐち Also written おおくち Meanings Noun big mouth; mouth opened wide boastful speech; tall talk; bragging; boasting Noun, の-adjective large amount; large quantity Antonym: 小口 (こぐち). Kanji 大 big. Read as おお. 口 mouth. Read as くち. Common phrases 大口を開ける (おおぐちをあける) to gape Words containing 大口 大口を叩く (おおぐちをたたく) to boast 大口顧客 (おおくちこきゃく) major customer 大口を開ける (おおぐちをあける) to gape Jinuma: Japanese Dictionary · Word lists