C:\>chcp
Active code page: 1252

C:\>type match_test_3.pl
#!perl

use strict;
use warnings;
use open qw( :encoding(Windows-1252) :std );

my $pattern = qr/\A\w+\z/;

for my $word (@ARGV) {
    my $result = $word =~ $pattern ? "matches" : "doesn't match";
    printf qq/The word "%s" %s the pattern %s\n/, $word, $result, $pattern;
}

C:\>perl match_test_3.pl Tšekissä Žena Œdipus Rex
"\x{009a}" does not map to cp1252 at match_test_3.pl line 12.
The word "T\x{009a}ekissä" doesn't match the pattern (?^:\A\w+\z)
"\x{008e}" does not map to cp1252 at match_test_3.pl line 12.
The word "\x{008e}ena" doesn't match the pattern (?^:\A\w+\z)
"\x{008c}" does not map to cp1252 at match_test_3.pl line 12.
The word "\x{008c}dipus" doesn't match the pattern (?^:\A\w+\z)
The word "Rex" matches the pattern (?^:\A\w+\z)

C:\>