When you put an array into a string or regex literal, it gets expanded to join($", @arr) (/cool guy here/ in this case.)

• One rather good solution is:

  my @arr = qw( cool guy here );
  my $str = "I am cool";
  
  my $re = "(?:" . (join '|', map quotemeta, @arr) . ")";
  if ($str =~ $re) {      # if ($str =~ /^$re$/) {
     print "Matched\n";   #    print "Equals\n";
  }                       # }
  [download]

  I used quotemeta because I presumed your array holds strings and not regexs.

• If your array contains many elements and you want a bit more speed, you could use Regexp::List.

  use Regexp::List qw( );
  
  my @arr = qw( cool guy here );
  my $str = "I am cool";
  
  my $re = Regexp::List->new(@arr)->list2re();
  if ($str =~ $re) {      # if ($str =~ /^$re$/) {
     print "Matched\n";   #    print "Equals\n";
  }                       # }
  [download]

  Regexp::List accepts a list of text. If you had a list of regexps, you'd use Regexp::Assemble instead.

• Of course, you could avoid regexs entirely.

  my @arr = qw( cool guy here );
  my $str = "I am cool";
  
  if (grep {index($str,$_)!=-1} @arr) {  # if (grep {$str eq $_} @arr) {
     print "Matched\n";                  #    print "Equals\n";
  }                                      # }
  [download]

Update: Added johngg's version for symetry. Originally, I only had the "Equals" version for grep.