There is 6 levels of password strength :

1. very weak : you should never ever use such a password
2. weak : use this password only for not private materials
3. medium : this password can be used for private stuff but must be changed very often
4. strong : your password is safe but you have to change it often
5. stronger : your password is strong and you may use it for private ressources
6. very strong : your password is very strong, great for you !