loose, tight
tangled
a tangled knot of arms and legs

double, overhand
granny, reef (esp. BrE), slip, square (AmE), etc.

do, tie
undo, untie
loosen, tighten

knot in
Tie a knot in the rope.

a knot in your stomach (figurative)
She felt a knot in her stomach which prevented her from speaking.

securely, tightly
loosely

around, round (esp. BrE)
She knotted the scarf loosely around her neck.

Knot is used with these nouns as the subject:
stomach

Knot is used with these nouns as the object:
cord, rope, scarf, shoelace, tie