We use "frighten" when we say like: "They frighten the cat!" In the sense that they were sending away the cat.
About big and Large, when we say that something is big, we say that is big. Large, we use in the case of sizes. Both word are adjectives, so... The dictionary can help us:
1. of more than average size, quantity, degree, etc.; exceeding that which is common to a kind or class; big; great: a large house; a large number; in large measure; to a large extent.
2. on a great scale: a large producer of kitchen equipment.
3. of great scope or range; extensive; broad.
* Big: adjective
1. large, as in size, height, width, or amount: a big house; a big quantity.
2. of major concern, importance, gravity, or the like: a big problem.
3. outstanding for a specified quality: a big liar; a big success.
scare and frighten are both adjectives. They mean the same thing like being afraid.
- I'm scared that I might fail the exam.
- I was frightened when the cat jump towards me.
big and large are also adjectives that mean the same. Big or large are used when something is more than the average. It is the opposite of small.
- The basketball is bigger than the golf ball.
- The shirt is large enough to become a quilt.