What does the prefix ful means?

The prefix "ful" means "full of" or "characterized by". It is used to form adjectives that describe a quality or characteristic.

Here are some examples:

* Beautiful: full of beauty

* Joyful: full of joy

* Hopeful: full of hope

* Painful: characterized by pain

* Successful: characterized by success

Essentially, "ful" indicates that something possesses a particular quality in abundance or is notable for that quality.