- explode: documentation ( source)
- in_array: documentation ( source)
- array_unique: documentation ( source)
<?php
$str = "cao isso pala só temp que pala vai temp aparecer temp aqui cao";
$match=array();
$return = array_unique(explode(' ', $str));
$badWords = array('cao', 'pala', 'temp');
for ( $i = 0; $i < count($badWords); $i++ )
if( in_array( $badWords[$i] , $return ) )
echo 'Yes matched -> ' . $badWords[$i];