Jargons and idioms, fixed expres

emo - very emotional.

Don't be so emo. Your boyfriend will be back next week.

frenemy - someone you think is your friend, but you know is really your enemy.

Has your frenemy got you worried?

groovy - very nice in a mellow sort of way (this is old slang from the 60s).

Groovy, man. Feel the good vibrations.

(Note: slang goes out of fashion quickly, so these examples might not be current.)

Recommendation

You can use the urban dictionary for definitions of slang. If a phrase is a slang, you'll find it there.

Jargon

Jargon could be explained as slang for business or enthusiasts. Jargon can be defined as words, phrases, or expressions that mean something specific in a particular profession. For example, there is a lot of jargon associated with the internet. It can also refer to specific words used in a sport, hobby or other activity. Jargon is known and used by those who are on the "inside" of a business or of some activity. 

Jargon Examples

cookies - used by programmers to track information on a user's computer that has accessed the internet.

We set a cookie when you first access our site.

birdie - used by golfers to state that the golf ball was put into the hole with one less golf stroke than expected on a hole.

Tim got two birdies on the back nine at the golf course.

chest voice - used by singers to indicate a style of singing that has chest resonance.

Don't push so hard with your chest voice. You'll hurt your voice!

Idiom

Idioms are words, phrases, or expressions that do not literally mean what they express. In other words, if you were to translate an idiom word for word in your own language, it most likely would not make any sense at all. Idioms are different than slang as they are used and understood by almost everyone. Slang and jargon are understood and used by a smaller group of people. There is a wide variety of idiom sources on this site for English learners. 

Idioms Examples