不ふ当とう利り得とく

ふ

と

う

り

と

く

Meanings

unjust enrichment; excessive profit

Legal and formal term for receiving a benefit without a valid legal basis, often used in civil law contexts.

They filed a lawsuit seeking restitution of unjust enrichment.

契けい約やくが無む効こうになった場ば合あい、不ふ当とう利り得とくとして支し払はらった金かねを返かえしてもらえることがある。

If the contract becomes void, you may be able to get back the money you paid as unjust enrichment.

不ふ当とう
不当 means 'unjust' or 'unreasonable' in general, while 不当利得 specifically refers to the legal concept of unjust enrichment.
利り得とく
利得 means 'gain' or 'profit' broadly; 不当利得 narrows it to gains obtained without legal justification.

Compound of 不当 (unjust) + 利得 (profit, gain). The term is a direct translation of the legal concept 'unjust enrichment'.