means To feel anxious or troubled about actual or potential problems, often turning the same fears over and over in your mind.

from From Old English 'wyrgan,' meaning to strangle or throttle — the word literally meant to choke. For centuries it kept that physical bite: a dog 'worries' a rat by seizing and shaking it by the throat, and people could 'worry' each other in a fight. Only later did the sense soften and turn inward, from gripping by the neck to being gripped by anxiety — as if your own cares had you by the throat. It's a cousin of German 'würgen,' to strangle.