difference between awful, horrible, and terrible

these words something that is very unpleasant

awful         - муу, муухай
horrible      - жигшмээр, ой гутмаар
terrible       - аймшигтай, аймаар

awful
1 (informal) very bad or unpleasant

• That is awful color
• They did not even offer to pay. oh that is awful
• to look/feel awful ( = to look / feel sick)
• there's an awful smell in here

2 (informal) used to emphasize (онцлох) something, especially that there is a large amount or too much of something.

• it's going to cost an awful lot of money
• there's not an awful lot of room

horrible

1(informal ) very bad or unpleasant; used to describe something that you don't like

• horrible weather / children / shoes
• the coffee tasted horrible
• i have a horrible feeling she lied to us

2 making you feel very shocked and frightened - synonym (terrible)

• a horrible crime / nightmare

3 (informal) (of people or their behavior ) unfriendly, unpleasant, unkind

• a horrible man
• my sister was being horrible to me all day

terrible

1 very unpleasant; making you feel very unhappy, upset, or frightened 

• a terrible experience
• what  terrible news
• i have just had a terrible thought

2 causing great harm or injury; very serious

• terrible accident
• he had suffered terrible injuries

3 (not before noun) unhappy or sick

• i feel terrible - i think i'll go to bed

4 (informal) of very bad quality; very bad

• a terrible meal
• your driving is terrible

5 (only before noun) used to show the great extent or degree of something bad

• a terrible mistake
• to be in terrible pain
• the room was in terrible mess

terrible very bad or unpleasant; making you feel unhappy, frightened, upset, ill, guilty, or disapproving: What terrible news! That's a terrible thing to say!awful (somewhat informal) very bad or unpleasant; used to describe something that you do not like or that makes you feel depressed, ill, guilty, or disapproving: That's an awful color. The weather last summer was awful.horrible (somewhat informal) very unpleasant; used to describe something that you do not like:The coffee tasted horrible.

 PATTERNS
terrible/awful/horrible for someonea(n) terrible/awful/horrible thinga(n) terrible/awful/horrible smellterrible/awful/horrible conditionsterrible/awful/horrible weatherterrible/awful/dreadful news

What is the difference between using words "terrible", "horrible" and "awful"?

They often can be used interchangeably. For instance:
It was a terrible/horrible/awful movie. You see here any one of the three could be used.
There is a slight difference, however. 
If I wanted to emphasize (онцлох) fear being involved, I would tend (хандлагатай байх) to use terrible. 
If I wanted to emphasize disgust (жигшилт), I would use horrible.
For lesser degrees of negativity, where something or someone is simply bad in some way, I would use awful.

horrible VS terrible - any real difference?

• I don't really see a difference between horrible and terrible in most situations. If you have doubts about whether one is more suitable, please write the sentences you're thinking about.

• Both sound the same, but their origins may help you understand:
  
  Also, terrible is often used for something very bad, such as a "terrible idea". While you could say "horrible idea", "horrible" in that case makes the idea not just bad but also dangerous. I guess, I consider "terrible" to be less extreme than "horrible", but you will often find it often doesn't matter.