The barbarity of Isis continues to defy the imagination.
Times, Sunday Times (2015)
With a land mass one and a half times that of the US, this is ice and snow on a scale which defies the imagination.
Times, Sunday Times (2012)
Definition of 'imagination'
imagination
(ɪmædʒɪneɪʃən)Explore 'imagination' in the dictionary
variable noun
Your imagination is the ability that you have to form pictures or ideas in your mind of things thatare new and exciting, or things that you have not experienced.
Definition of 'defy'
defy
(dɪfaɪ)Explore 'defy' in the dictionary
verb [no passive, no cont]
If something defies description or understanding, it is so strange, extreme, or surprising that it is almost impossible to understand or explain.