The only free and comprehensive online etymological dictionary of the Spanish language
aburrir (Verb) "to bore"
13th cent. From Latin abhorrere "to loathe," "to recoil" from ab- "away from" (see ab-) and horrere "to dread," "to shudder" (see horror).
Indo-European
Romance
Portuguese avorrir, Galician aburrir, Catalan aborrir, French abhorrer, Italian aborrire, Romanian borî

"An art of the boring, by lexical necessity, cannot pre-date romantacism.... Earlier one may have fidgeted, felt listless or succumbed to accidie.... Comparable to the graduate vitiation of affect in the meaning of the words dreadful," "awful," "terrible," etc., "boredom" marks the historical boredom with abhorrence (orthographically the Spanish aburrir still maintains closer ties with the Latin "abhorrere," although it has undergone the same semantic shift)." ~ J. Phillips, "Beckett's Boredom" in Essays on Boredom and Modernity (2009)