say i created a drop down list of days using data validation.
Now if i type few words (in the cell which has the data validation) say "su",is it possible that the list in data validation narrow the choices and show only sunday.
Paramnayak, I guess you meant with "Auto Completion" if your current selection is already listed in above then it should definitely be appeared.(like as your example just typing "su" show the "sunday" if sunday is selected previously in the list then it should be appeared if not then, it will not)
Auto completion....through data validation is not possible as far as I know,I would suggest to look for VB solution.