Compare cell value from Col 1 to all cell values in Col 2 and identify dups.

I have 1 workbook 1 worksheet that contains 2 columns. Each column contains Customer Names. I want to take each Customer Name from each cell from A1 through A9999 one at a time and compare it to Column B and determine if it exists in Column B.

If it exists in Column B then i want to say in the adjacent cell POSS DUP. Here is an example:

Column A1 has Customer Name "The ABC Corp". Somewhere in Column B will have a Customer Name similar to The ABC Corp, lets say, in Column B somewhere is a Customer Name that is "The ABCXYZ Corp". Even though these are not exact matches because ABC from Column A1 is similar to The ABCXYZ Corp i want the adjacent column to POSS DUP.