These words all refer to inviting or complainant attitudes towards other people, and are alike in suggesting either an openness or willingness to make the acquaintance of others. In its broadest sense, gregarious is applied to animals as well as people. It involves a basic tendency to associate with one’s fellows, implying a natural disposition for group living: Men and sheep are both gregarious animals. In another sense, gregarious applies to people who actively seek the society of others, preferring company to solitude, but even in this sense the implication of wanting to be with others of one’s own kind is present: students who are so gregarious they are unable to spend a single evening alone for the sake of their studies. On the other hand, the more dialectal or "folksy" term, sociable , implies the seeking of a personal acquaintanceship, often in conformity with one of the prevailing cultural mores: a housewife who considers it sociable to invite a new neighbour in for morning coffee with the other women in the street. Social is more formal than sociable , and applies more often in this sense to an individual’s temperament than to an event, often defining one aspect of a person: the social side of his character; She’s become very social lately, giving at least one party a month. When applied to temperament, outgoing is akin to social but more often suggests a sociological context: an outgoing personality. Outgoing indicates a person who is not indrawn, inhibited or shy, but on the contrary one who expresses himself openly and makes acquaintances easily. Because such traits are attractive to most people, outgoing is often linked with other favourable terms: a sweet, outgoing child; a pleasant, warm, outgoing teacher.

Where the preceding words focus on the active individual whose social antennae "go out" to other people, affable and amiable indicate receptivity or accessibility to the gestures of others. Etymologically, affable means capable of being spoken to, i.e., easy to approach. It suggests a benign and courteous attitude rather than one actively seeking new friends; The easy, affable manner of the lecturer endeared him to his audience. Amiable has more of a note of kindliness, and suggests an openness to friendship. Unlike affable , amiable may also refer to a disagreement or dispute that is free from antagonism or ill feeling: An amiable rivalry existed between the two old friends.

Friendly has a wide variety of applications. It may , like amiable , mean free from ill feeling: a friendly argument. It may mean acting as or typical of a friend: friendly advice; Inviting us to stay the night was a friendly and hospitable gesture. Friendly may suggest an openness to a personal or intimate relationship based on the individual natures or interests of the people concerned; in this sense it differs from the more impersonal amiable and affable and the less individually-oriented gregarious .

• She was gregarious but not friendly ; she liked to be surrounded by crowds and admirers but assiduously avoided personal relationships with any of them; He was an amiable sort – never said a harsh word about anyone – but no one ever got very friendly with him; Einstein had an affable nature, quick to appreciate wit and with considerable personal charm, but he was nevertheless known intimately by very few, and could not be called friendly .

But friendly is also used more broadly to refer to kindliness in people and to the absence of antagonism or menace in animals.

• He was a friendly fellow, always ready to lend a helping hand when needed; The dog seemed friendly enough until I tried to pet him.

Cordial means warm and hearty, and suggests sincerity of feeling as well; it is nowadays used most often of formal situations rather than personal ones involving the private lives of individuals: A cordial welcome was accorded the visiting minister of state; a cordial greeting. Its formal context and tone should not be interpreted as somehow vitiating the sincerity of feeling the word connotes; it simply suggest a formal but genuine expression of feeling: a long and cordial relationship between the violinist and his protégé.