Undue Influence - Taking any fraudulent or unfair advantage of another's weakness of mind, or distress or necessity.

Unearned Increment - An increase in value of real estate due to no effort on the part of the owner.

Unit Cost-in-Place Method - A method for determining cost or cost of reproducing an improvement.

Unlawful Detainer - An action at law to evict a person or persons occupying real property unlawfully.

Usury -On a loan, claiming a rate of interest greater than that permitted by law.