Next time it would be efficient to post what you have tried yourself.
As unprivileged user you will be able to hide files from other users using access permissions by changing the "other" and "group" bits. For example running 'chmod 0400 ~/somefile' as unprivileged user sets the file permissions to readable for you but not other unprivileged users ...but you can not use discretionary access permissions to hide a file from root. (If the files contents are worth it you could opt for file encryption instead. While GnuPG is one of the most secure and compatible forms, you could also use something simple like
which works on all platforms having access to OpenSSL.)
openssl enc -e -bf -in ~/someFileName -out ~/someOtherFileName