From Latin 'importāre' (to carry into) — something important 'carries weight into' a situation; significance as cargo.
Of great significance or value; having a marked effect or influence.
From French 'important,' from Italian 'importante,' from Medieval Latin 'importantem' (present participle of 'importāre,' to be of consequence, to carry in), from Latin 'importāre' (to bring in, carry in), composed of 'in-' (into) + 'portāre' (to carry), from PIE *per- (to lead, to pass over). Something 'important' literally 'carries weight into' a situation — it brings significance. The word took a circuitous path into English: Latin to Italian to French to English, arriving in the mid-sixteenth century. The Italian humanists of the Renaissance gave 'importante' its abstract sense of 'mattering,' extending the Latin commercial meaning
The adjective 'important' is etymologically the present participle of the verb 'import' — something important is literally something 'importing,' something actively carrying weight into a situation. English lost this grammatical connection centuries ago, but Romance languages preserve it clearly: Italian 'importante' is transparently the present participle of 'importare' (to matter). The most common adjective in English for 'significant' is, at its root, a