The original idea of this root was:
Which makes it awfully similar to the root *su̯enk-. Research shows no connection between the two, but we all know that science is just one many possible opinions.
(kidding, of course)
The main English member of the family is the word to wink, which probably evolved from moving in a staggering, tottering way and then at some point shifted toward that kind of movement for just the eyelids… I know… sounds stupid.
Other English relatives are winch, wench and wince.