boggle
verb /ˈbɒɡl/
  /ˈbɑːɡl/
 [intransitive] (informal)Verb Forms
Idioms | present simple I / you / we / they boggle |    /ˈbɒɡl/   /ˈbɑːɡl/  | 
| he / she / it boggles |    /ˈbɒɡlz/   /ˈbɑːɡlz/  | 
| past simple boggled |    /ˈbɒɡld/   /ˈbɑːɡld/  | 
| past participle boggled |    /ˈbɒɡld/   /ˈbɑːɡld/  | 
| -ing form boggling |    /ˈbɒɡlɪŋ/   /ˈbɑːɡlɪŋ/  | 
- boggle (at something) to be slow to do or accept something because you are surprised or shocked by it
- Even I boggle at the idea of spending so much money.
 
Oxford Collocations DictionaryBoggle is used with these nouns as the object:- mind
 
Word Originlate 16th cent.: probably of dialect origin and related to bogle, a phantom or goblin and bogey ‘thing that causes fear’. 
Idioms 
something boggles the mind 
(also the mind boggles)
- (informal) if something 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!’