Other forms: smarter, smartest, smarts
Smart means quick-thinking — the one who works out the answer while everyone else is still reading the question. It also means neatly turned out: a smart shirt, smart shoes, the note on the invitation that says wear something smart.
Which sense comes first depends on where you are. In America, smart is mainly about brains. In Britain, the clothes sense is just as loud: a smart restaurant, smart casual, you look very smart. Machines took the word next — smartphone, smart TV, smart meter, smart motorway; anything with a chip making decisions inside it. There is an older verb too, still alive: your eyes smart in smoke, a slap smarts, and you can smart at criticism for days. Careful with people: calling someone smart in the clothes sense means tidy and well dressed, not good-looking.
1adjectivecleverQuick to understand things and good at working them out.
“That was a smart answer for a nine-year-old.”
2adjectivesmartNeat, clean and well dressed; stylish in a tidy way.
“He looked very smart in his grandfather's jacket.”
synonyms: elegant, well-dressed
3adjectivedeviceOf a device: run by a small computer, so it can adjust what it does.
“The heating is on a smart meter now.”
4adjectiveforcefulQuick and forceful.
“She set off at a smart pace and left us behind.”
5verbstingTo sting with a sharp pain, or to feel hurt by something said.
“His eyes smarted in the onion fumes.”
Too few real examples of this word to estimate which sense is commonest.
Also accepted in games: clever, intelligent
Smart began as pain. Old English smeortan meant to hurt or sting, from a Proto-Germanic root smertaną, to hurt or ache, and behind that a Proto-Indo-European root meaning to bite. German schmerzen and Swedish smärta still mean simply to hurt. The sharpness stayed when the word crossed to wit: a smart remark is one that stings.
Proto-Indo-European
*(s)merd- — to bite, sting
Proto-Germanic
*smertaną — to hurt, ache
Proto-West Germanic
*smertan
Old English
*smeortan — to smart
Middle English
smerten
English, today
smart
From Middle English smerten, from Old English smeortan (“to smart”), from Proto-West Germanic smertan, from Proto-Germanic smertaną (“to hurt, ache”), from Proto-Indo-European (s)merd- (“to bite, sting”). Cognate with Scots smert, Dutch smarten, German schmerzen, Danish smerte, Swedish smärta.
Etymology from Wiktionary, CC BY-SA