"mad, insane, crazy," 1903, perhaps from dip + -y (2), but the exact signification is unclear. Another theory connects it with dipsomania.
Crazy; foolish; whimsically silly; kooky: so strange and dippy as to have come from the brain of Tolkien/ Depardieu at his dippiest
[1900+; origin unknown; perhaps fr dip, ''head,'' in the expression off one's dip, ''crazy''; perhaps fr dipsomaniac; perhaps fr Romany divio, ''mad, madman'']