The following code isn't intended to be a cut-n-paste solution, but rather a demonstration of a technique you can use to search for multiple keywords and do replacements based on those keywords.

my %replacements = qw/men     women
                      houses  homes
                      cats    dogs
                      venus   mars
                      carpet  rug
                      full    empty/;

my $string = "men cats houses venus carpet full";

for my $keyword ( keys %replacements ) {
    my $re = qr/\b$keyword\b/;
    $string =~ s/$re/$replacements{$keyword}/gi;
}
print "$string\n";

__OUTPUT__
women dogs homes mars rugs empty
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Hope this helps. There are other similar idioms, and other different idioms that accomplish the same thing, but this one seems to be more or less what you're asking for.