A person can be afraid of something and still be able to do it if they tried. However, someone who is terrified of something has a much greater amount of fear related to the object or idea. If they are really terrified, they could become emotionally damaged by being what they are afraid of.
Ex: Cal does not like being around a lot of people and is terrified of crowds. As a remedy for his problem, his friend Mike planned Cal's birthday party and only invited five of his best friends.
Ex: If you are terrified of small, dark places, you should live somewhere where the land is flat and full of open space. You would feel safe and sound in places like East Anglia or Somerset.
You can also say someone is terrified to do something if that action scares them to a strong or large degree.
Ex: James is so terrified to meet new people that sometimes he won't even leave his room. His friends have to plead with him to get him to come to a party or big event.
The phrase scared of is synonymous with afraid of. Both expressions are completely interchangeable, describing a person having a fear of a particular object, person, or idea.
Ex: Most children are scared of the dark, but when they grow up the fear goes away. However, I have a friend named Lauren who still sleeps with a nightlight, and she is 30 years old.
Ex: People all over the world say their biggest fear is public speaking. They're so scared of being judged or disliked by others that they avoid talking in front of any large group of people