puerile

Puerile is an adjective used in English to describe behavior, remarks, or attitudes that are childish, immature, or trivial. It often implies a failure to take a matter seriously or to engage with it in a mature or thoughtful way. The term can apply to jokes, opinions, or actions that are considered silly or lacking in substance.

Etymology: from Latin puerilis "boyish, of a boy," from puer "boy." It entered English in the early modern period, with evolving connotations toward disparagement of childishness and lack of seriousness. Common collocations include puerile humor, puerile remarks, puerile excuses, and puerile arguments. The word is often pejorative and is used to critique perceived immaturity.

Usage notes: Puerile is typically applied to human behavior and speech and is less suitable for describing physical age. It contrasts with terms like juvenile (more neutral about age), immature (focus on development), or frivolous (lighthearted, not necessarily childish). Some argue that the term can be loaded or dismissive, so it should be used with care, particularly in formal writing. Related nouns include puerility or puerileness, though these forms are more rare and often clumsy.