my @AoA = (
    ['a','b','c'],
    ['a','b','c'],
    ['a','b','d'],
    ['a','b','d'],
);

##</code><code>##

my @uAoA = (
    ['a','b','c'],
    ['a','b','d'],
);

##</code><code>##

use strict;
use warnings;
use Data::Dumper;

my @AoA = (
    ['a','b','c'],
    ['a','b','c'],
    ['a','b','d'],
    ['a','b','d'],
);

my (%h, @uAoA);
for (@AoA) {
    push @uAoA, $_ if !$h{join $;, @$_}++;
}

print Dumper \@uAoA;