my $words = {
  'foo' => [ 'nn', 'nns' ],
  'bar' => [ 'nvbg', 'np' ],
};

my $lookup = 'foo';
print $words->{$lookup}->[0]; # Would print 'nn', the first tag
foreach my $tag (@{$words->{$lookup}}) {
  # This would print the tags for a specified word, in the order in which they were defined
  print $tag . "\n";
}
# To add a new word and/or tag:
push @{$words->{'baz'}}, 'nps';
# To delete a tag:
@{$words->{'baz'}} = grep { $_ ne 'nps' } @{$words->{'baz'}};
# To check for a specific tag:
if ( grep { $_ eq 'nps' } @{$words->{'baz'}} ) { ... }