Venial, a.
Etymology: [OF. venial, F. véniel, L. venialis, from venia forgiveness, pardon, grace, favor, kindness; akin to venerari to venerate. See Venerate.]
1. Capable of being forgiven; not heinous; excusable; pardonable; as, a venial fault or transgression. So they do nothing, 't is a venial slip. Shak.
2. Allowed; permitted. [Obs.] "Permitting him the while venial discourse unblamed." Milton. Venial sin (R. C. Theol.), a sin which weakens, but does not wholly destroy, sanctifying grace, as do mortal, or deadly, sins. -- Ve"ni*al*ly, adv. -- Ve"ni*al*ness, n. Bp. Hall.
Shades of meaning
Venial (L. venia, pardon) signifies capable of being pardoned, and, in common use, capable of being readily pardoned, easily overlooked. Aside from its technical ecclesiastical use, venial is always understood as marking some fault comparatively slight or trivial. A venial offense is one readily overlooked; a pardonable offense requires more serious consideration, but on deliberation is found to be susceptible of pardon. Excusable is scarcely applied to offenses, but to matters open to doubt or criticism rather than direct censure; so used, it often falls little short of justifiable; as, I think, under those circumstances, his action was excusable. Protestants do not recognize the distinction between venial and mortal sins. Venial must not be confounded with the very different word venal. Compare venal.