You could use Thomas' StringContains function from the task repository once you download it:
{TASKREPOSITORY(d6ca5c3b-02bc-432e-8438-fa8006fe79dd|StringContains(Success(String);Success:Failure(String);:(String))|)}
From the help:
Returns true if string contains search string. Multiple searchstrings allowed
haystack: The string to be searched
needles: A string with characters that should be searched for. Separated by delimiter
delimiter: The delimiter used in needles
Example:
haystack = abcde
needle = x;d
delimiter = ;
Searches string abcde for x or d. Returns true
Be advised though this function will return True if the word is also part of a word, i.e. "Successful" as the haystack in my example will also return True.