The phrases “scared of ” and “afraid of ” have similar meanings – to have fear or to be frightened of someone or something. For example, you may say, “I am afraid of (or scared of) snakes”. Afraid and scared are generally followed by the preposition “of “.
You could also use the verb forms “to fear” or “to frighten” to express a similar meaning to the above: I fear snakes -or- I am frightened by snakes. Fear and frighten are regular verbs ending in “ed” for the past and past participle forms.
Afraid is also used to indicate when a speaker wishes to be polite, sorry or apologetic. Example: I’m afraid I can’t attend your party and I’m afraid Mr. Smith cannot see you until tomorrow.