A slow but possible and fun solution: Quantum::Superpositions. Tested; compiles, runs, and works correctly (I think). Needs Class::Multimethods.

#!/usr/bin/perl
use Quantum::Superpositions;

print "What is your insult? ";
chomp (my $input = <>);

my @matching = qw/disk duck deck/;
die if ($input eq any(@matching)); # could also use @matching[0..2]
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:-)