use strict;
use warnings;

my $str="this is abc and bcf and xyz and ijklmn but not abbc";
my @words = split ' ', $str;
my @incWords = grep {
      my %uniq = map {$_ => 0} split ''; $_ eq join '', sort keys %uniq
  } @words;

print "@incWords";

##</code><code>##

is abc bcf xyz ijklmn not