Meaning of “unimaginable” - Learner’s Dictionary

unimaginable

adjective uk us /ˌʌnɪˈmædʒɪnəbl/

Something that is unimaginable is difficult to imagine because it is so bad, good, big, etc.:

unimaginable pain/wealth
unimaginably adverb

(Definition of “unimaginable” from the Cambridge Learner’s Dictionary © Cambridge University Press)