Something important matters enough that you cannot leave it out. The one bag you carry onto the plane yourself; the phone call you take in the middle of dinner because of whose name is on the screen.
It stretches from small to enormous without changing shape: an important email, an important election, the most important person in the room. Two prepositions do most of the work, and they split by job. Something is important TO a person, as in this is important to me, and important FOR a purpose, as in sleep is important for memory. The noun is importance, and careful writing says a matter of great importance. The adverb turns up mainly inside more importantly, which steers a listener towards the bigger point, and self-important is the sour cousin, meaning somebody who thinks they matter far more than they do.
1adjectiveimportantMattering a great deal, with a real effect on what happens.~86%
“The important thing is to arrive before the doors close.”
synonyms: significant, crucial
2adjectivepowerHaving power or influence over others.~14%
“She was an important figure in the party for twenty years.”
Shares are an estimate: a language model read 29 sentences found in the wild and placed 29 of them on a sense — a count of our sample, not a measurement of English.
Important came into Middle English from Medieval Latin importans, the same shape you can hear in import, the idea of what a thing carries in with it. Old English had said heah and hefig, high and heavy, for the same idea. The Latin newcomer pushed both of them out of the way.
Medieval Latin
importāns
Middle English
important
English, today
important
From Middle English important, from Medieval Latin importāns. by surface analysis, import + -ant. Displaced native Old English hēah and hefiġ.
Etymology from Wiktionary, CC BY-SA