What was wrong with vizzini saying "inconceivable?"?

Question

Why doesn't it mean what he thinks it means? What does it mean?

Answer 1

Main Entry: in·con·ceiv·able  

Pronunciation: \ˌin-kən-ˈsē-və-bəl\

Function: adjective

Date: 1624

: not conceivable: as a: impossible to comprehend b: unbelievable

— in·con·ceiv·abil·i·ty  \-ˌsē-və-ˈbi-lə-tē\ noun

— in·con·ceiv·able·ness  \-ˈsē-və-bəl-nəs\ noun

— in·con·ceiv·ably  \-blē\ adverb

Vizzini kept calling things that were actually happening: a ship overtaking them, the masked man climbing the cliffs of despair, the masked man defeating Inigo, he kept calling these things impossible to comprehend even though they were happening.

Answer 2

Not sure who vizzini is, but "inconceivable" simply means something so remote you can't even imagine it (happening).

It will never happen.