means An uncomfortable, tickling sensation on the skin that makes you want to scratch, or by extension a restless craving to do something.

from From Old English giccan, 'to itch,' a verb that wriggled its way through the Germanic family — it has cousins in German jucken and Dutch jeuken, all describing that same maddening prickle. The figurative sense of 'a nagging desire' (as in 'the seven-year itch') came later, the body's literal nuisance lending its name to the mind's.