What does 可愛い Kawaii mean?

Kawaii means cute. The translation is accurate and it undersells the word, because in Japanese this is not only an adjective but the name of an aesthetic with a traceable history and a set of rules.

The characters, and why they mislead

可 (ka) means able or permissible; 愛 (ai) means love. Read literally the compound suggests lovable, which is tidy and is largely a coincidence. The characters were fitted to an existing word rather than the word being built from them.

The older form is かはゆし (kawayushi), and its sense sat closer to something that makes you wince on someone's behalf: pitiable, painful to look at, the feeling of seeing something small and defenceless. The modern warmth is a drift from a word that originally described discomfort. That history is still faintly audible in how the word gets used about things that are slightly pathetic.

The part that is a system

Cute exists everywhere. What is specific here is that Japan developed cuteness into an organised visual language with a datable origin. The scholarship on this, principally Sharon Kinsella's work on cute culture, traces the modern form to the 1970s, when schoolgirls began writing in a rounded, childlike hand with small drawings mixed into the characters. The style spread, was picked up commercially, and hardened into a design vocabulary.

From there it reached stationery, packaging, mascots for city councils and police departments, and eventually the visual conventions of manga and animation. The large eyes and reduced features that English speakers think of as an anime style are the same system applied to faces.

What it is used on

Almost anything. A pen, a font, a way of laughing, a small dog, a bento arrangement, a bad drawing. The register is casual and the frequency is high enough that translating every instance as cute produces English that sounds strange, because English reserves cute for a narrower set of subjects and gets awkward when applied to an adult.

The criticism, which is worth including

Kinsella and others have argued the aesthetic carries a cost: it prizes helplessness, and when the standard is applied to women it rewards behaving as less capable than you are. That reading is contested, including by people inside the culture who see the style as a claim on autonomy rather than a concession.

Both positions are held seriously by people who have thought about it, which is more than can be said for the usual English treatment of the word as a synonym for adorable.