From theLatin adjectivefortis, fortem, fromOld Latinforctis,fortis, fromProto-Indo-European*bʰerǵʰ-(“to rise, high, hill”). Compare the same semantic development inFrenchfort,Occitanfòrça,Ligurianfoart (attested inMenton,France). In older Romanian, the word was also used as a freestanding adverbial, in addition to simply as an intensifier.
foarte