venal, venial

Venal or venal describes a corrupt official or authority, one willing to accept bribes for favors--
We won't see any real reform until this venal administration is voted out of office.
The matter came before a venal judge, who decided in the company's favor.

Venal may also describe a thing unlawfully bartered or sold, such as a contract or court decision--
It was a venal contract; they bribed a city official to get it.
The jury was suspected of accepting bribes in return for a venal acquittal.

Venial or venial describes a  trivial or pardonable sin; a minor transgression--
It was a venial error, and easily overlooked.
The offense was venial; the penance will be light.

Now that you know that, you can say--
"In City Hall, a venal agreement is considered a venial sin."