【Venial】 , 【pardonable】  are applied to faults, sins, or errors and mean of such a character as not to warrant punishment or the imposition of a penalty.

【Venial】  in most use implies an opposition to grave , serious , or grievous <he had learned to see what was really criminal in what he had done, and what was  【venial】  —Trollope >  and in theological use to mortal (see mortal under DEADLY ); consequently it often means trifling , not willful , or harmless .

【Pardonable】 implies that such excuse or justification may be offered for the fault or error that it is not worthy of consideration.