unretrievable vs irretrievable

unretrievable and irretrievable both are adjectives.

Word	Noun	Adjective	Verb	Adverb
unretrievable	No	Yes	No	No
irretrievable	No	Yes	No	No

As adjectives, unretrievable and irretrievable are synonyms defined as:

unretrievable and irretrievable: impossible to recover or recoup or overcome

unretrievable (adjective)	irretrievable (adjective)
impossible to recover or recoup or overcome	impossible to recover or recoup or overcome