RichThesaurus
few cards shy of a full deck
vs
mad as a hatter
few cards shy of a full deck
adj
mentally deranged; demented; insane.
mad as a hatter
adj
Demented or crazy.
How often have the words
few cards shy of a full deck
and
mad as a hatter
occurred in a corpus of books?
(source:
Google Ngram Viewer
)