*ger-

The core idea of this root was:

turning, coiling up, crooked
(with some sense of tension)

English sources only mention this root as the origin of creep, but according to German sources, the root is also the origin of words like cramp, crotch, cripple, cramp and also craft.
They all do have a notion of coiling up of being crooked, so it’s at least helpful for learners to group them together.

The word craft evolved from the German sense of (physical) strength which itself comes from the notion of “flexing, coiling up” muscles. In English, the word then shifted from strength toward skill.