| 意思表示 | ishi hyōji | declaration of intention |
| 心裡留保 | shinri ryūho | mental reservation (saying something you don't mean) |
| 虚偽表示 | kyogi hyōji | sham (fictitious) declaration made in collusion |
| 錯誤 | sakugo | mistake |
| 詐欺 | sagi | fraud |
| 強迫 | kyōhaku | duress / intimidation |
| 取消し | torikeshi | rescission (cancellation with retroactive effect) |
| 取り消す | torikesu | to rescind / cancel |
| 無効 | mukō | void (invalid from the start) |
| 追認 | tsuinin | ratification (later approval) |
| 善意 | zen'i | in good faith (not knowing the fact) |
| 悪意 | akui | in bad faith (knowing the fact) |
| 無過失 | mukashitsu | without negligence |
| 過失 | kashitsu | negligence |
| 重大な過失 | jūdai na kashitsu | gross negligence |
| 第三者 | daisansha | third party |
| 代理権 | dairiken | authority of agency |
| 無権代理 | muken dairi | unauthorized agency (acting without authority) |
| 表見代理 | hyōken dairi | apparent agency |
| 代理人 | dairinin | agent |
| 復代理 | fukudairi | sub-agency |
| 催告 | saikoku | formal demand / notice requesting action |
| 制限行為能力者 | seigen kōi nōryokusha | person with limited legal capacity |
| 未成年者 | miseinensha | minor (under 18) |
| 成年被後見人 | seinen hikōkennin | adult ward (person under guardianship) |
| 被保佐人 | hihosanin | person under curatorship |
| 法定代理人 | hōtei dairinin | statutory agent (e.g. parent, guardian) |
| 詐術 | sajutsu | deception (pretending to have full capacity) |
| 取得時効 | shutoku jikō | acquisitive prescription (gaining ownership by long possession) |
| 消滅時効 | shōmetsu jikō | extinctive prescription (loss of a claim by time) |
| 時効 | jikō | prescription (time-based gain/loss of rights) |
| 援用 | en'yō | invoking (asserting) prescription |
| 占有 | sen'yū | possession |
| 所有権 | shoyūken | ownership |
| 所有者 | shoyūsha | owner |
| 登記 | tōki | registration (in the real property register) |
| 対抗要件 | taikō yōken | perfection requirement (to assert rights against third parties) |
| 対抗 | taikō | to assert (a right) against another party |
| 背信的悪意者 | haishinteki akuisha | third party acting in bad faith against trust (not protected) |
| 二重譲渡 | nijū jōto | double sale (selling the same property to two buyers) |
| 物権 | bukken | real right (right over a thing) |
| 債権者 | saikensha | creditor |
| 債務者 | saimusha | debtor |
| 債権 | saiken | claim / receivable |
| 債務 | saimu | obligation / debt |
| 抵当権 | teitōken | mortgage |
| 根抵当権 | neteitōken | revolving mortgage |
| 質権 | shichiken | pledge |
| 留置権 | ryūchiken | right of retention (keep the item until paid) |
| 先取特権 | sakidori tokken | statutory lien |
| 物上代位 | butsujō dai'i | subrogation to proceeds (e.g. mortgage extends to rent/insurance) |
| 法定地上権 | hōtei chijōken | statutory superficies (land-use right created by law) |
| 連帯保証 | rentai hoshō | joint and several guarantee |
| 連帯債務 | rentai saimu | joint and several obligation |
| 保証人 | hoshōnin | guarantor |
| 保証契約 | hoshō keiyaku | guarantee contract |
| 極度額 | kyokudogaku | maximum guaranteed amount |
| 根保証 | nehoshō | revolving guarantee (covers unspecified future debts) |
| 催告の抗弁 | saikoku no kōben | defense of demand (ask creditor to demand from debtor first) |
| 検索の抗弁 | kensaku no kōben | defense of reference (ask creditor to seize debtor's assets first) |
| 相殺 | sōsai | set-off (cancelling mutual debts) |
| 弁済 | bensai | performance / payment of a debt |
| 更改 | kōkai | novation (replacing an obligation with a new one) |
| 混同 | kondō | merger (creditor and debtor become the same person) |
| 賃貸借 | chintaishaku | lease |
| 賃貸人 | chintainin | lessor / landlord |
| 賃借人 | chinshakunin | lessee / tenant |
| 賃借権 | chinshakuken | leasehold right |
| 借地権 | shakuchiken | land lease right (for owning a building) |
| 借地借家法 | shakuchi shakka hō | Land and Building Lease Act |
| 定期借地権 | teiki shakuchiken | fixed-term land lease (no renewal) |
| 定期建物賃貸借 | teiki tatemono chintaishaku | fixed-term building lease (no renewal) |
| 正当事由 | seitō jiyū | just cause (needed for landlord to refuse renewal) |
| 更新 | kōshin | renewal |
| 敷金 | shikikin | security deposit |
| 造作買取請求権 | zōsaku kaitori seikyūken | right to demand purchase of fixtures |
| 必要費 | hitsuyōhi | necessary expenses (e.g. repairs) |
| 有益費 | yūekihi | beneficial expenses (improvements) |
| 転貸 | tentai | sublease |
| 区分所有 | kubun shoyū | condominium unit ownership |
| 専有部分 | sen'yū bubun | exclusive (private) unit |
| 共用部分 | kyōyō bubun | common areas |
| 規約 | kiyaku | bylaws (of a condominium) |
| 集会 | shūkai | general meeting (of unit owners) |
| 議決権 | giketsuken | voting right |
| 建替え | tatekae | rebuilding (of a condominium) |
| 管理者 | kanrisha | administrator / manager |
| 相続人 | sōzokunin | heir |
| 被相続人 | hisōzokunin | decedent (the deceased) |
| 相続放棄 | sōzoku hōki | renunciation of inheritance |
| 相続 | sōzoku | inheritance |
| 配偶者 | haigūsha | spouse |
| 直系尊属 | chokkei sonzoku | lineal ascendants (parents, grandparents) |
| 直系卑属 | chokkei hizoku | lineal descendants (children, grandchildren) |
| 兄弟姉妹 | kyōdai shimai | siblings |
| 代襲相続 | daishū sōzoku | inheritance by representation (grandchild inherits in place of deceased child) |
| 欠格 | kekkaku | disqualification |
| 廃除 | haijo | disinheritance by court |
| 遺言 | yuigon | will / testament |
| 遺留分 | iryūbun | legally reserved portion (minimum share for heirs) |
| 遺産分割 | isan bunkatsu | division of the estate |
| 法定相続分 | hōtei sōzokubun | statutory share of inheritance |
| 契約不適合 | keiyaku futekigō | non-conformity with the contract (defect in quality/quantity) |
| 追完請求 | tsuikan seikyū | demand for cure (repair/replacement) |
| 代金減額請求 | daikin gengaku seikyū | demand for price reduction |
| 損害賠償 | songai baishō | damages (compensation) |
| 解除 | kaijo | termination of contract |
| 手付 | tetsuke | earnest money deposit |
| 手付金 | tetsukekin | earnest money deposit |
| 共有 | kyōyū | co-ownership |
| 持分 | mochibun | ownership share |
| 保存行為 | hozon kōi | act of preservation |
| 引渡し | hikiwatashi | delivery / handover |
| 売買契約 | baibai keiyaku | sale and purchase contract |
| 売主 | urinushi | seller |
| 買主 | kainushi | buyer |
| 事務管理 | jimu kanri | management of another's affairs without mandate |
| 不当利得 | futō ritoku | unjust enrichment |
| 不法行為 | fuhō kōi | tort (unlawful act) |