boggle
[verb]
Synonyms: demur, balk, gag, jib, scruple, shy, stick, stickle, strain, stumble, botch, blow, bobble, bollix, bungle, cobble, goof (up), gum (up), louse up, mess, stagger, dumbfound, nonplus

[TahlilGaran] English Synonym Dictionary ▲

bog‧gle /ˈbɒɡəl $ ˈbɑː-/ verb
[Date: 1500-1600; Origin: Perhaps from bogle; ⇒ bogey]
the/your mind boggles, (also something makes the/your mind boggle, something boggles the/your mind) informal if your mind boggles when you think of something, it is difficult for you to imagine or accept it:
The sheer amount of data makes the mind boggle.
the/your mind boggles, at
My mind boggles at the amount of work still to do.

[TahlilGaran] Dictionary of Contemporary English ▲