use warnings;
use strict;
use feature qw/fc/;
use Text::CSV_XS;
use List::Util qw/uniq/;
use Data::Dump;

my $csvfile = $ARGV[0];
my %table;
open my $fh, '<', $csvfile or die "$csvfile: $!";
my $csv = Text::CSV_XS->new({binary=>1, auto_diag=>2});
while ( my $row = $csv->getline($fh) ) {
	push @{$table{ fc($row->[0]) }}, $row->[2];
}
$csv->eof or $csv->error_diag;
close $fh;
$_ = [uniq @$_] for values %table;

dd \%table;

__END__

{
  "ip whitelist"         => ["IP access list"],
  "ip whitelist entries" => ["IP access list entries"],
  "whitelist"            => ["allow", "access list", "access-list"],
  "whitelist entries"    => ["access list entries"],
  "your whitelist"       => ["your access list"],
}