$re = '/(?!.*\bMaster\b).* tells you, .*/m';
$str = '(Soandso tells you, "Hello")
But I need it to exclude any string containing the word "Master."
(Yourpet tells you, "Attacking creature Master.")
(Yourpet tells you, "The \\b makes it only exclude the exact word, so this is found: Masterpiece.")';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php