un ‧ i ‧ ma ‧ gined /ˌʌnɪˈmædʒənd◂, ˌʌnɪˈmædʒɪnd◂/ BrE AmE adjective [usually before noun] literary
[ Word Family: adjective : ↑ imaginable ≠ ↑ unimaginable , ↑ imaginary , ↑ imaginative ≠ ↑ unimaginative , ↑ unimagined ; noun : ↑ imagination , ↑ imaginings ; adverb : ↑ unimaginably , ↑ imaginatively ; verb : ↑ imagine ]
so good, large, great etc that it is hard to imagine