As a verb imprison

is to put in or as if in prison; confine.

As an adjective unimprisoned is

not imprisoned.

Free is a synonym of unimprisoned.

As adjectives the difference between free and unimprisoned

is that free is (label) unconstrained while unimprisoned is not imprisoned.

As an adverb free

is without needing to pay.

As a verb free

is to make free; set at liberty; release; rid of that which confines, limits, embarrasses, or oppresses.

As a noun free

is (australian rules football|gaelic football) abbreviation of free kick.

Imprisoned is an antonym of unimprisoned.

As a verb imprisoned

is (imprison).

As an adjective unimprisoned is

not imprisoned.

In transitive terms the difference between imprison and reimprison

is that imprison is to put in or as if in prison; confine while reimprison is to imprison again.

As adjectives the difference between alphabetical and letterless

is that alphabetical is pertaining to, furnished with, or expressed by letters of the alphabet while letterless is without the presence or use of alphabetical letters.

As a noun letter

is a letter (character).

As an adjective letterless is

without the presence or use of alphabetical letters.

As nouns the difference between illiteracy and unletteredness

is that illiteracy is (uncountable) the inability to read while unletteredness is the state or condition of being unlettered; illiteracy.

As nouns the difference between tumour and retrocession

is that tumour is (oncology|pathology) an abnormal growth; differential diagnosis includes abscess, metaplasia, and neoplasia while retrocession is retrocession.

As a verb surface

is .

As a noun retrocession is

retrocession.

As nouns the difference between interior and retrocession

is that interior is the inside of a building, container, cavern, or other enclosed structure while retrocession is retrocession.

As an adjective interior

is within any limits, enclosure, or substance; inside; internal; inner.