The phrase "unthinkable act" refers to something that is so shocking or unimaginable that it is beyond what most people believe is possible or acceptable. Full definition
Leaving one's child behind is a totally unthinkable act to me. (bookbrowse.com)
Johann zeroes in on one Dr. Josef Mengele, a friendly - looking monster who has committed unthinkable acts against children, including Simon's. (dvdizzy.com)
With less than a month to go until its release, the final trailer has arrived online for the upcoming supernatural horror The Bye Bye Man which stars Carrie - Anne Moss, Doug Jones, Faye Dunaway, Lucien Laviscount, Douglas Smith, Michael Trucco and Cressida Bonas; take a look below after the official synopsis... People commit unthinkable acts every day. (flickeringmyth.com)