$s = 'php or python and java and someone too';
$words_to_remove = array("or", "and", "one");
foreach ($words_to_remove as &$word)
{
$word = '/\b' . preg_quote($word, '/') . '\b/';
}
$s = preg_replace($words_to_remove, '', $s);
echo $s;
/*
run:
php python java someone too
*/