echo inside a for loop lists files matching the output pattern

I have a problem with the following for loop:

X="*back* OLD"
for P in $X
do
echo "-$P"
done

I need it to output just:

-*back*
-OLD

However, it lists all files in the current directory matching the *back* pattern. For example it gives the following:

-backup.bkp
-backup_new.bkp
-backup_X
-OLD

How to force it to output the exact pattern?

>Solution :

Use an array, as unquoted parameter expansions are still subject to globbing.

 X=( "*back*" OLD )
 for P in "${X[@]}"; do
     printf '%s\n' "$P"
 done

(Use printf, as echo could try to interpret an argument as an option, for example, if you had n in the value of X.)