 <pre><code>private static List&lt;string&gt; wordsToRemove = "DE DA DAS DO DOS AN NAS NO NOS EM E A AS O OS AO AOS P LDA AND".Split(' ').ToList(); public static string StringWordsRemove(string stringToClean) { return string.Join(" ", stringToClean.Split(' ').Except(wordsToRemove)); } </code></pre> <p>Modification to handle punctuations:</p> <pre><code>public static string StringWordsRemove(string stringToClean) { // Define how to tokenize the input string, i.e. space only or punctuations also return string.Join(" ", stringToClean .Split(new[] { ' ', ',', '.', '?', '!' }, StringSplitOptions.RemoveEmptyEntries) .Except(wordsToRemove)); } </code></pre>