venial \VEE-nee-uhl\ (adjective) - Capable of being forgiven; not heinous; excusable; pardonable.
"Martin's latest error was a venial one, although that he made so many of them so frequently was not something which was lost on those higher-up in the chain of command."
Venial comes from Latin venia, "grace, indulgence, favor." It is not to be confused with venal, which means "capable of being bought; salable; open to bribery," and comes from Latin venum "sale." Remember that venial, like sin, has an i in it.