Untreatability is a derived term of untreatable.

As a noun untreatability

is the state or condition of being untreatable.

As an adjective untreatable is

not treatable; impossible to treat.

Untreatably is a derived term of untreatable.

As an adverb untreatably

is in an untreatable way.

As an adjective untreatable is

not treatable; impossible to treat.

As a noun twist

is a twisting force.

As a verb twist

is to turn the ends of something, usually thread, rope etc., in opposite directions, often using force.

As an adjective untwistable is

impossible to twist; not twistable.

Untwistable is a derived term of twistable.

As adjectives the difference between twistable and untwistable

is that twistable is capable of being twisted while untwistable is impossible to twist; not twistable.

As adjectives the difference between veined and unveined

is that veined is having veins or veinlike markings while unveined is not veined; not having veins.

As a noun vein

is .

As an adjective unveined is

not veined; not having veins.

As a verb ventilated

is past tense of ventilate.

As an adjective unventilated is

not ventilated, lacking ventilation.

As verbs the difference between tether and untether

is that tether is to restrict something with a tether while untether is to undo by removing a tether.

As a noun tether

is a rope, cable etc that holds something in place whilst allowing some movement.

As verbs the difference between remove and unthread

is that remove is (label) to move something from one place to another, especially to take away while unthread is to remove a thread from.

As a noun remove

is the act of removing something.

As a noun thread

is thread (computing: unit of execution).

As a verb unthread is

to remove a thread from.