Adjective
mindboggling (comparative more mindboggling, superlative most mindboggling)
(chiefly US) Alternative form of mind-boggling
Because it is mindboggling as to why you feel it okay to blurt out these statements, almost as if it was reflexive. Source: Internet
Most mindboggling, though, were those instances down the stretch where he survived the long, brutal exchange. Source: Internet
It's mindboggling how much effort and wealth has been poured into this place. Source: Internet
The detail put into creating the cover story is mindboggling. Source: Internet