unimagined

Word family  noun imagination imaginings adjective imaginable ≠ unimaginable imaginary imaginative ≠ unimaginative unimagined verb imagine adverb unimaginably imaginatively

 Longman Dictionary of Contemporary English 5++朗文当代英语 5++LDOCE 5++朗文 5++un·i·ma·gined /ˌʌnɪˈmædʒɪnd◂/ adjective [usually before noun] literary  so good, large, great etc that it is hard to imagine 〔好、大等得〕无法想象的，想象不到的

Examples from the Corpus

unimagined• a place of unimagined beauty• Behind the honeysuckle and the hollyhocks there was revealed a life of hitherto unimagined degradation.• Stepan is falling ill without knowing it; his unspoken, unimagined destination is delirium and death.• Others see a new golden age of business and technology that will lift the market to unimagined heights.• Commentators are a maligned lot and deserve some credit for disseminating enthusiasm for sport on a hitherto unimagined scale.

un·i·ma·gined adjectiveChineseSyllable  

so it Corpus that large, is etc great good,

unimagined
un‧i‧ma‧gined /ˌʌnɪˈmædʒənd◂, ˌʌnɪˈmædʒɪnd◂/ adjective [usually before noun] literaryso good, large, great etc that it is hard to imagine