hairy: covered with hair, shaggy of body
This is the plain root sense of the word: hair-covered, rough to the touch. Hebrew built it from the ordinary noun for hair, so it pictures a body that is noticeably shaggy rather than smooth.
It appears only in the Jacob and Esau story, describing Esau himself and the feel of the hands Jacob disguises. From this image of the hairy, shaggy creature the same word came to name the shaggy animal, the male goat, which is its far more common use.