These words all refer to undesirable acts or circumstances that are worthy either of criticism, sorrow or pity. Reprehensible exclusively stresses disapproving criticism for egregiously bad behaviour or character: the reprehensible diffidence of public officials in taking stands on the crises of the day; a reprehensible criminal who had robbed great numbers of people without the slightest twinge of regret. Opprobrious is the strongest word in this group. It refers to something that not only merits criticism but looked on with disdain or scorn. There is often an implication of general rather than merely personal censure involved in anything opprobrious : the opprobrious commercialization of Christmas.

While culpable refers to something deserving of censure, its main stress may be on an attempt to assign guilt or blame, and hence punishment, for an accident, misdeed or failure: culpable negligence; He displayed culpable ignorance in handling what was only a routine personnel problem. Culpable is milder than the foregoing words in that it would not be used for outrageous or egregious violations of a legal or moral code. Blameworthy , like culpable , is concerned with assigning guilt for failure or misbehaviour; the tone of the word may be factual and neutral: an investigation to determine which of the officials involved in the recent scandal were the most blameworthy . More generally, the word can express censure, although it seldom suggests the moral outrage of opprobrious : a blameworthy lack of concern for the impoverished.

Regrettable is mildest word in this group. It need not denote a critical attitude of censure at all, but rather a sympathetic understanding of someone’s failings: a regrettable lack of decisiveness that marred an otherwise brilliant and accomplished man. It contrasts with the previous words even more dramatically when it expresses pity for circumstances beyond human control: It is regrettable that such a great talent died so young. Sometimes the word is used in a polite or genteel way to express disapproval in terms of sympathetic disappointment: your regrettable absence from my dinner party. The word can even be used more forcefully as an ironic understatement for a severely critical reaction: I find it regrettable that Miss Smith chose to display her inadequacies to us so conclusively by taking on one of the most demanding roles in all of drama.

In many ways, deplorable is an intensification of regrettable . On one hand, it can express consternation and distress over what may be no one’s fault: the deplorable accident that crippled her for life. But when it is used critically, it is harsher than regrettable and does not mask its criticism in irony or understatement: deplorable living conditions; a deplorable lack of human compassion. Like regrettable , deplorable would not be used for outrageously hardened, cruel or brutal behaviour.