An imp is a European mythological being similar to a fairy or demon, frequently described in folklore and superstition. The word may perhaps derive from the term ympe, used to denote a young grafted tree.

What is a impish person?

: having or showing a playful desire to cause trouble : playful and mischievous. See the full definition for impish in the English Language Learners Dictionary. impish. adjective. imp·​ish | \ ˈim-pish \

Is impish positive or negative?

impish has a negative connotation as an imp is a michevious/trouble making creature. im not sure you could describe someone in a good way with impish. you could however use playful, because it still has the michevious connotation, but in a positive way.