title: Find words only containing given characters : RegEx
body: <p>I have set of words. For example,</p>
  
  <pre><code>abc, adb, acb, cab, abcc, abk, bacc
  </code></pre>
  
  <p>I want to find words which only have </p>
  
  <blockquote>
    <p>abc</p>
  </blockquote>
  
  <p>so, result I need is</p>
  
  <pre><code>abc, acb, cab, abcc, bacc
  </code></pre>
  
  <p>I need to find this using Regular Expressions.
  <br />Can anyone please help me.</p>