<?php
$arr = [];
$arr[] = 'За';
$arr[] = 'За©';
$arr[] = 'Против';
$pattern = '/\A[а-яА-Я]*\Z/';
foreach($arr as $string) {
    $matches = [];
    var_dump(preg_match($pattern, $string, $matches));
    var_dump($matches);
    var_dump($string);
}
?>