In lang=en terms the difference between crouch and writhe
is that
crouch is to bend, or cause to bend, as in humility or fear while
writhe is to twist or contort the body; to be distorted.
As nouns the difference between crouch and writhe
is that
crouch is (obsolete) a cross or
crouch can be a bent or stooped position while
writhe is (knot theory) the number of negative crossings subtracted from the number of positive crossings in a knot.
As verbs the difference between crouch and writhe
is that
crouch is (obsolete) to sign with the cross; bless or
crouch can be to bend down; to stoop low; to lie close to the ground with legs bent, as an animal when waiting for prey, or in fear while
writhe is to twist, to wring (something).