crackpot

crackpot  {n.},  {attrib. adj.},  {informal}
1.  {n.}
An eccentric person with ideas that don't make sense to most other people.
Don't believe what Uncle Noam tells you — he is a crackpot.
2.  {attrib. adj.}
That's a crackpot idea.
Categories: adjective informal noun

'crackpot' on video