If you are given the choice between acts that are
venal and those that are
venial, go for the venial. Although the two words look and sound alike, they have very different meanings and histories.
Venal demonstrates the adage that anything can be had if the price is high enough and the morals are low enough. That word originated with the Latin
venum, which simply referred to something that was sold or for sale. Some of those transactions must have been rather shady because by the mid-1600s,
venal had gained the sense of corruption it carries today.
Venial sins, on the other hand, are pardonable, the kind that show that everyone makes mistakes sometimes. That forgiving term descends from
venia, Latin for "favor," "indulgence," or "pardon."