These words refer to behaviour unbecoming to an adult. Childish suggests lack of control or restraint and carries possible connotations of petulance, irrationality, impatience and self-preoccupation: a childish insistence that everyone listen to him; a childish fear of the dark. The word is so negative in tone that it is seldom now used to describe a young person, or even his understandable limitations. Childlike is also not used to describe the young, since it would be obviously tautological. Used of adults, however, it gives a tone in strong contrast to childish . It suggests having the freshness, curiosity or honesty of the young; it gives possible connotations of innocence, lack of inhibition, zest or eagerness: a childlike ability to look at paintings unhampered by preconceptions; He felt an almost childlike wonder at the beauty of the forest. In uses where it is least positive, it still suggests a touching lack of experience or sham: her childlike naïveté in agreeing to go to his hotel room for a nightcap; a childlike unconcern for the rank and title of his assembled guests.

Unlike the foregoing, immature and juvenile may be used in factual reference to the young or things pertaining to them: an immature seedling; a juvenile court. In this case, immature is more general since it can refer to any living thing not fully developed, whereas juvenile refers specifically to young human beings. In reference to adults, both words are disapproving in tone, juvenile somewhat less and immature considerably less than childish .

• I suppose we are all a little immature , but while I have been guilty of juvenile behaviour from time to time, he is downright childish .

Juvenile indicates behaviour typical of a young person nearing adulthood, and thus may suggest intemperance, extremism, laziness, excessive zeal or idealism, or thoughtless inconsiderateness: a juvenile inability to compromise; a juvenile habit of seeing everything in black and white; juvenile snap judgements. In recent usage, immature has become a fad word for any failing in rationality or lack of understanding in group relations. As such it would be inclusive of behaviour suggested by childish or juvenile , except that overuse has made it milder sounding, since almost any failing can be considered immature : an immature wish to be divorced at the first sign of friction; an immature dependence on others for his opinions. Also, the word might specifically refer to behaviour that falls short of that appropriate to a person’s chronological age: immature of him to go off courting as though he were still a young man.

Infantile and puerile are the most disapproving of all these words. From their construction, both might be thought capable of neutral description, but puerile is almost never used in this way, and infantile only when used as a technical word; even in such contexts infant is often preferred: infantile paralysis; infantile (or infant ) behaviour. Similarly one would refer to a boy boyhood (not puerile ) dreams. Infantile , when applied to other than infants, is in fact an intensification of childish and suggests complete self-absorption and helplessness: his wife’s infantile tantrums. The most formal of these words, puerile is also more vague in its condemnation. It can suggest anything callow, weak, stupid, or inept. At its most vague, it can mean simply worthless: puerile efforts to negotiate; the pianist’s puerile performance.