I just found this when googling to solve the same problem, and had to make a minor change to the solution to make it work in my situation, as I had 2 similar substrings, "Sun" and "Sunstruck" to search for. The offered solution was locating the wrong entry when searching for "Sun". Data in column B
I added another column C, formulaes C1=" "&B1&" " and changed the search to =COUNTIF(B1:B10,"* "&A1&" *")>0, the extra column to allow finding the first of last entry in the concatenated string.