(a.) Inclined to worry or fret; also, causing worry or annoyance.

aggravating annoying bothering bothersome chafing disquieting distressful distressing disturbing exasperating fretting galling harassing importunate importune irking irksome irritating pesky pestering pestiferous pestilent pestilential plaguesome plaguey plaguing provoking teasing tiresome tormenting troublesome troubling upsetting vexatious vexing wearisome worrying