wouldn't know (something) if (one) fell over one

wouldn't know (something) if (one) fell over one

Is too oblivious or ignorant to realize or recognize a very obvious thing. You're no expert. You wouldn't know a Rembrandt if you fell over one. Tim's not much of a scout. He wouldn't know a promising pitcher if he fell over one.
See also: fell, if, know, one, over
Farlex Dictionary of Idioms.
See also:
  • wouldn't know (something) if it hit (one) in the face
  • keep (someone or oneself) in ignorance
  • keep in ignorance
  • live under a rock
  • the blind leading the blind
  • blind leading the blind
  • blind leading the blind, the
  • put somebody wise
  • put someone wise
  • put wise