I can see that ASPELL's dictionaries are there : ftp://ftp.gnu.org/gnu/aspell/dict/0index.html I guess you could put all of the 5-letters-long words in 1 file (1 word on each line). Let's call it "wordbase.txt". Then all you have to do is :

# make the wordbase into an array
open(FH, "wordbase.txt");
my @words = <FH>;
close FH;

# select the word randomly in the wordbase
my $random_index = int(rand($#words));
my $random_word = $words[$random_index];

print "$random_word\n";
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