stopwords contain a list of stopwords,

That error means $stopwords is not declared (my or our). If you have a list of stop words, I presume it's in @stopwords rather than $stopwords? If so, you need a second loop to scan over your list of stop words.

WORD:
foreach $word (@data) { 
   foreach my $stopword (@stopwords) { 
      next WORD if $word eq $stopword;
   }

   push(@lessWords, $word);
}

print "@lessWords\n";
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Instead of using a second loop, you could speed up things greatly (if you have more than a couple of @words) by using a hash.

my %stopwords;

# Create an element in the hash for each stop word.
undef @stopwords{@stopwords};

foreach $word (@data) { 
   next if exists $stopword{$word};
   push(@lessWords, $word);
}

print "@lessWords\n";
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i am puting the stoplist sperated by \n from the file to the array of stopwords

open( LIST, "stopwords.txt" ) or die "$!";
my @stopwords = <LIST>;
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as you suggested to use hash instead can you please tell me how i can put the stopwords read from file to the hash thanks

I already did:

open( LIST, "stopwords.txt" ) or die "$!";
my @stopwords = <LIST>;
chomp(@stopwords); # <- was missing

my %stopwords;

# Create an element in the hash for each stop word.
undef @stopwords{@stopwords};
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or using less memory:

# Create an element in the hash for each stop word.
my %stopwords;
open( LIST, "stopwords.txt" ) or die "$!";
while (<LIST>) {
   chomp;
   undef $stopwords{$_};
}
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Update: Added chomp.

#!/usr/bin/perl

use strict;

# declare the variables

my $stopwords = "word";
my @data = qw( a word another and a verb a noun a phrase);

my @lessWords;

foreach my $word (@data) 
{ 
    if ($stopwords !~ / $word /) 
    {
         push @lessWords, $word; 
    } 


}
print "@lessWords\n";
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In almost all situations, variables that you create should be lexicals.

You need to change your declaration to:

my $stopwords = "whatever_you_set";

Before your code, that is.

You must be using use strict;

HTH.

i am using these statements

open( LIST, "stopwords.txt" ) or die "$!";
my @stopwords = <LIST>;
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yes i am using strict

I guessed correctly! See my answer.

unless ( grep { / $word / } @stopwords ) {
  push @lessWords, $word;
}
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