something boggles the mind

Từ điển Oxford Advanced Learner 8th

sth boggles the ˈmind idiom
(also the mind ˈboggles) (informal)if sth boggles the mind or the mind boggles at it, it is so unusual that people find it hard to imagine or accept
•The vastness of space really boggles the mind.
•‘He says he's married to his cats!’ ‘The mind boggles!’
compare ↑mind-boggling
Main entry: ↑boggle_idiom