### Clue: One overlooked Rennaissance painter, a very important person (5)
### Answer: TITAN 
 ### Explanation: Definition: very important person
  TITiAN(Renaissance painter) minus(*overlooked*) I(*one*).  Defn:  From Greek mythology, extended to mortals to mean one of enormous size, power, strength, influence, and, I guess, *importance* qualifies, eg. a titan of industry