Find all palindromes of four characters or less

I got this far that is the code searches the bigtextfile for words with 4 characters or less then store those characters to a palindromes text file. The problem I am having is that I don't know how to find the palindromes. The 4 character words that are stored to palidromes text file must be a palindrome word. Any help is appreciated.

awk '{

   for\(i=1;i<=NF;i\+\+\) 

   \{

     if\(length\($i\)<5\) 

     \{print $i\}

   \}

   \}' bigTextFile.txt  > palindromes.txt

Maybe you should ask your teacher.

(thread closed)