use strict; use warnings;
use List::Util 'all';

# see below for how to properly create your hash
my %words = (
    foo => 1,
    bar => 1,
    baz => 1,
    qux => 1,
);

my @must_exist = (
    'bar',
    'qux',
);

my $all_found = all { exists $words{ $_ } } @must_exist;

if ( $all_found ) {
    ...
}

##</code><code>##

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

##</code><code>##

@array = ('foo', 'bar', 'baz', 'qux');
%hash = map { $_ => 1 } @array;

##</code><code>##

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

##</code><code>##

if ( exists $hash{'foo'} and exists $hash{'bar'} ) {
    ...
}

##</code><code>##

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