my @words = qw( SA NV LTD CO LLC );

##</code><code>##

my ($re) = map qr/$_/i, join '|', map quotemeta, @words;

##</code><code>##

use Regexp::List qw( );
my $re = Regexp::List->new(modifiers => 'i')->list2re(@words);

##</code><code>##

while (<>) {
   chomp;

   s/^ (?: $re \s+ )+//x;
   s/  (?: \s+ $re )+//xg;

   print("$_$/");
}