Vocabulary consisting only from characters you are able to read
直火
じかび
open fire, direct heatmix
開放
かいほう
open, throw open, liberalization, liberalisationsuru
開店
かいてん
opening (of a shop)suru
開閉
かいへい
opening and shuttingsuru
開会
かいかい
opening of a meetingsuru
開通
かいつう
opening, open, taking effect, becoming activesuru
視点
してん
opinion, point of view, visual pointmix
反対
はんたい
opposition, resistance, antagonism, hostility, contrast, objection, dissension, reverse, opposite, vice versajlpt3, jlpt4, leda1, suru
反抗
はんこう
opposition/resistance/insubordination/defiance/hostility/rebellion/(P)leda1, suru
最適
さいてき
optimum, the most suitablemix
順序
じゅんじょ
order, sequence, proceduremix
体制
たいせい
order, system, structure, set-up, organization, organisationmix
常微分方程式
じょうびぶんほうていしき
ordinary differential equationmath
鉱石
こうせき
ore, mineral, crystalmix
器官
きかん
organ (of body), instrumentmix
構成
こうせい
organization, organisation, configuration, compositionsuru
体系化
たいけいか
organization, organisation, systematization, systematisationsuru
原点
げんてん
origin (coordinates), starting pointmix
由来
ゆらい
origin, source, history, derivation, reason, destinyall
原意
げんい
original meaningmix
原状
げんじょう
original statemix
目新しい
めあたらしい
original, novel, newadj
独自
どくじ
original, peculiar, characteristic, proprietarymix
元来
がんらい
originally, primarily, essentially, logically, naturallymix
元祖
がんそ
originator, founder, pioneer, inventormix
他
ほか
other (esp. places and things)/the restadj, leda1
外
ほか
other place, the restjlpt5
余人
よじん
others, other people; others, other peoplemix
場違い
ばちがい
out-of-place, inappropriate, sticking out like a sore thumbmix
宿
やど
outcasts (those from Kamakura period to the Edo period, common around the Kyoto region); inn, lodgingmix
屋外
おくがい
outdoors, alfrescomix
外出
がいしゅつ; そとで
outing, trip, going out; (n,vs) outing, trip, going outsuru
域外
いきがい
outside the areamix
向こう
むこう
over there, opposite direction, across the wayjlpt3, jlpt5
優勝
ゆうしょう
overall victory, championshipsuru
飲み過ぎ
のみすぎ
overdrinking, excessive drinkingmix
重なり
かさなり
overlapping, piling, stackingmix
苦しみ
くるしみ
pain, anguish, distress, suffering, hardshipmix
一対
いっつい
pair (of screens or vases, etc.)mix
紙幣
しへい
paper money, notes, billsmix
月極駐車場
つきぎめちゅうしゃじょう
parking lot rented on a monthly basismix
役割
やくわり
part, assigning (allotment of) parts, role, dutiesmix
部位
ぶい
part, position (in a whole, i.e. body)mix
参加者
さんかしゃ
participant, entrantmix
関与
かんよ
participation, taking part in, participating in, being concerned insuru
別れ
わかれ
parting/separation/farewell/(lateral) branch/fork/offshoot/division/section/(P)jlpt3