What does "cast off" mean?

Discard, reject, as in He cast off his clothes and jumped in the pool. This term was already used figuratively in Miles Coverdale's translation of the Bible (1535): “Thy mother ... that hath cast off her housebonds and her children” (Ezekiel 16:45).

Let go, set loose, as in He cast off the line and the boat drifted from the dock. [Second half of 1600s]

In knitting, to finish the last row of stitches, that is, take the stitches off the needle and form a selvage. For example, Your sweater is finished; I just have to cast off. [Late 1800s] Also see cast on, def. 1.