To cast off is to finish knitting by securing the last row. Cast off loosely.
Doing it too tightly makes an edge that will not stretch, which ruins a neckline. In sailing to cast off means to let go the ropes, which is a quite separate use.
1phrasecast offTo finish knitting by securing the last row.
“Cast off loosely or the jumper will not go over anybody's head.”
cast off is a phrase.
Also accepted in games: bind off
Practised in Knitting & Sewing