In thinking about "supererogatory" it occurred to me that there ought to be a word "erogatory" meaning called for, obligatory. No can find.
Did find "suberogatory" defined by user as "blameworthy but not obligatory". I have trouble thinking what conduct would be both blameworth and obligatory. (The Devil made me do it)?
The same site had word new to me: "deontic logic". Couln[t find "deontic" but did find dandy word "deontology":
deontology
n.
5< Gr deon (gen. deontos), that which is binding, necessity < dein, to bind (see DIADEM) + 3LOGY6 the ethical doctrine which holds that the worth of an action is determined as by its conformity to some binding rule rather than by its consequences
de[on[to[log[i[cal 7dc 9n#t! l9j4i k!l8
adj.