If a text in div contain a specific word you can use includes method on string ($(selector).text().includes('your-text-search'))

if ( $('.btn-download').text().includes('download') ) {
  $('.dynamic').hide();
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<div class="dynamic">
  This text is hidden if another div contains the word "download"
</div>
<div class="something">
  <div class="btn-download">
  If this text has the word "download" the div with class "dynmaic" is hidden
  </div>
</div>

This can help, I'm not an expert but try to edit.

$(document).ready(function() {
  $("#dynamic").click(function() {
    var res = $('#dynamic').text();
    if (res == "value") {
      var hide = document.getElementById("something");
      hide.style.display = "none";
    }
  });
});

Your example code needs jQuery. This is a solution using ECMAScript 5 or older and jQuery.

jQuery(document).ready(function($){
  if ( $('.btn-download').text().indexOf('download') !== -1) {
    $('.dynamic').hide();
  }
});

Please check the fiddle https://jsfiddle.net/1sx39q6h/

For jQuery + ECMAScript 6, you have the solution of @jeremy-denis.