I remember how me and my friends used to use weak as an insult.
Look, we’re on the last letters. I’m out of material.
Weak showed up in the early fourteenth century, coming from the Old Norse work veikr. That word stems from the Proto Germanic waikwaz (yield) and wikanan (bend), so something that is pliable and easy to move is weak. It can further be traced back to the Proto Indo European weik, bend or wind, and the ancestor of several words, including vicarious and weak homophone week.
Week and weak are related. I’m not even sure how to react to that.
University of Texas at Austin Linguistic Research Center