Excusable a.
Etymology: [L. excusabilis: cf. F. excusable. See Excuse.]
That may be excused, forgiven, justified, or acquitted of blame; pardonable; as, the man is excusable; an excusable action. -- Ex*cus"a*ble*ness, n. -- Ex*cus"a*bly, adv. The excusableness of my dissatisfaction. Boyle.
Shades of meaning
Fernald has no entry of its own for excusable; he lists it under venial.
Where he writes about it:
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. — from venial