an ironfisted policy
弾圧政策
an ironic smile
苦笑い
an irregular liner
不定期船
an irregular physician
無免許医師
an irregular pulse
不整脈
an irregular road
でこぼこ道
an irregular verb
不規則変化動詞
an irresistible attraction
たまらない魅力
an irreverent reply
不敬な返答
an irrigation ditch
潅漑用水路
an island nation
島国
an isolated fortress
孤立無援の要塞さい
an isolation hospital [ward]
隔離病院［病棟］
an isosceles triangle
二等辺三角形
an issue extraneous to the subject
主題とは無関係の事柄
an issue of blood
出血
an issue of great interest
重要な事柄
an item of clothing
服１着
an item on the agenda
議題
an object of attention [worship]
注目の的［崇拝の対象］
an object of ridicule
嘲笑の的
an oblate sphere
偏球
an oblique angle
斜角（◇直角とその倍数以外の角度）
an oblique cone
斜円錐
an oblique glance
横目でちらっと見ること
an obscene phone call
いたずら電話
an obscure artist
無名の芸術家
an obscure corner of the room
暗い部屋のすみ
an obscure figure
ぼんやりした人影
an obscure meaning
あいまいな意味
an obscure style
わかりにくい文体
an observatory that affords a panoramic view of the city
市を一望できる展望台
an obsolete word
廃語，死語
an obstacle between a mother and her son
母親と息子を阻む障害
an obstacle to success
成功の妨げ
an obstinate headache
がんこな頭痛
an obstructed view seat
（野球場などで）視界がさえぎられて見にくい席
an obtuse angle
鈍角
an obvious [a definite] advantage
明確な利点
an obvious liar
見え見えのうそつき
an obvious truth
明白な真理
An occasional beer is my only indulgence.
たまにビールを飲むのが唯一の道楽です
an occasional gleam of intelligence
折にふれてひらめく知性
an occasional mistake
たまたま犯した誤り
an occasional thunderstorm
時々来る雷雨
an occupational counselor
就職指導員
an occupational disease
職業病
an occupational hazard
職業上の危険
an occupational [a company] pension scheme
企業年金制度
an ocean [a lake] basin
海盆［湖盆］
