All these words can apply to acts that go against the codes which society sets up to regulate social behaviour. Unethical in its generality has the widest range of uses, applying particularly to any act that barms another person: unethical electioneering practices such as bribery, appeals to bigotry and anonymous pamphleteering. The word has a popular connotation, as well, that suggests a milder sort of breach, one that is unfair but not so apparently harmful to someone: insisting that it was unethical to curry favour with an instructor. Unethical finds its greatest use when associated with wrongful practices in certain professions; doctors and lawyers, for example, are occasionally charged with unethical behaviour. By contrast, immoral , at its most general, can point to much more grave or serious harm: believing that it was immoral to sanction violence in the midst of social unrest. Here, unethical would seem a hair-splitting way of typifying the action under discussion. In popular usage, immoral more concretely points to sexual misbehaviour: parents so hopelessly old-fashioned and puritanical that they forbade dancing to their children as an immoral activity. Immoral , of course, can be applied like unethical to whatever one disapproves of: sects that view films and dancing as immoral .

Unscrupulous and unprincipled both apply to people willing to do anything for their own gain, regardless of whom they harm. Unscrupulous is the less condemnatory of the two, suggesting someone who would commit any venial breach of taste, conduct or manners to advance himself, though perhaps stopping short of anything outright illegal or at least anything that would get him into trouble: an unscrupulous executive manager who would betray any confidence in his vain hope of ingratiating himself with the management. Unprincipled , by contrast, suggests an even more rapacious attitude: an unprincipled dope pedlar who made a fortune by ruining hundreds of lives.

Amoral points to behaviour that is at variance with society’s codes of behaviour because of ignorance, indifference or a more or less principled rejection of these values: the amoral lives of new bohemians who see old values as nothing more than institutionalized cruelty. Unmoral and non-moral means not within the realm of morality.

• A baby is unmoral ; Meteorology is a non-moral study.