my %hash = @allwords; #puts array in hash to search / compare.

##</code><code>##

(
    'word1' => 'word2',
    'word3' => undef,
)

##</code><code>##

$ perl -MData::Dump -e '@a = qw{b c a}; %h = @a; dd \%h'
{ a => undef, b => "c" }

##</code><code>##

my %hash = map { $_ => 1 } @allwords;

##</code><code>##

$ perl -MData::Dump -e '@a = qw{b c a}; %h = map { $_ => 1 } @a; dd \%h'
{ a => 1, b => 1, c => 1 }

##</code><code>##

if (exists $hash{'word1' && 'word2' && 'word3'}) { ...

##</code><code>##

$ perl -E 'my $x = "a" && "b" && "c"; say $x'
c

##</code><code>##

if ( grep { $_ eq 'word1' && 'word2' } @allwords ) { ...

##</code><code>##

$ perl -E '$_ = "a"; my $x = $_ eq "a" && "b"; say $x'
b

##</code><code>##

$ perl -MO=Deparse -e 'grep { $_ eq "word1" && "word2" } @a'
grep {'word2' if $_ eq 'word1';} @a;
-e syntax OK
$ perl -MO=Deparse,-p -e 'grep { $_ eq "word1" && "word2" } @a'
grep({(($_ eq 'word1') and 'word2');} @a);
-e syntax OK

##</code><code>##

$ perl -E 'my @x = qw{b c a}; say scalar grep { /^(?:a|b|c)$/ } @x'
3
$ perl -E 'my @x = qw{x y z}; say scalar grep { /^(?:a|b|c)$/ } @x'
0
$ perl -E 'my @x = qw{x c y a b z}; say scalar grep { /^(?:a|b|c)$/ } @x'
3

##</code><code>##

my $regex = ...;

if (@matchwords == grep { /$regex/ } @allwords) { ...