mind-boggling
adjective /ˈmaɪnd bɒɡlɪŋ/
  /ˈmaɪnd bɑːɡlɪŋ/
(informal)- very difficult to imagine or to understand; extremely surprising
- a problem of mind-boggling complexity
 - It’s mind-boggling to me that this is allowed to happen.
 
More Like This Descriptive compound adjectives with parts of the bodyDescriptive compound adjectives with parts of the body- back-breaking
 - ear-splitting
 - eye-popping
 - gut-wrenching
 - hair-raising
 - lung-busting
 - jaw-dropping
 - mind-boggling
 - nail-biting
 - rib-tickling
 - side-splitting
 - spine-chilling
 - stomach-churning
 - toe-curling