You did already import the data via the Read Excel operator, right? Then just add a Filter Examples operator. With RapidMiner 5 you then can filter on one column. Select attribute_value_filter as condition_class. Then the parameter_string
column1 != .*badWord.*
will keep all rows where column1 does not contain the string "badWord".
To match only whole words, your filter should look like this:
column1 != != ^(.+\s)*badWord(\s.*)*$
The cryptic syntax used here are regular expressions
Google for that term to get more information.