Venial from imperfect work: could be mortal in kind, softened by how it is done
Some acts would be mortal by kind, yet imperfect performance keeps them from being judged as war on charity—hence venial.
Imperfect performance alone can keep an otherwise mortal kind from being judged as war on God’s love.
Latin
VIII. Venialia ex imperfectione operis ea dicunt, quae tametsi ex genere suo, mortalia esse possent, tamen ob imperfectionem operis venialia efficiuntur: quia videlicet, sola imperfectio operis facit, ut cum charitate & amore Dei pugnare non judicentur.