HOT

1. Sexy( adj./ slang)
*Sam says his new girlfriend is hot

2. Stolen (adj./ slang) 
*That stereo is hot!I

BRAINY

1. very intelligent, like a genius.

*Sue always does well on tests because she's brainy

SLAVE DRIVER

If someone is a “slave driver” it means that they make other people work incredibly hard.  No one likes a slave driver.  They are so difficult to work for and they don’t make your life happy.  Many successful business people are slave drivers, but that doesn’t mean they are nice people.  It just means they know how to make their staff work super hard.

A real “slave” is someone who has been taken away from their family and forced to work for zero or very low wages.  When black people first went to the USA, many of them were slaves for the white men.  This is a terrible period of history, but the point is to let you know what the meaning of a slave is.  Now a “slave driver” isn’t as serious as the original meaning, it just means a boss who makes their staff work too hard for too little pay.

* Example:  I quit my job because my boss was too much of a slave driver.

SLACKER

A “Slacker” is a person who is really lazy and does less work than they should do.  People can beslackers in school or at work.  If you do this sometimes, it’s called “slacking off“.

*  He is a smart guy but he’s such a slacker.  I think the boss is going to fire him if he doesn’t improve.

* She slacked off the whole semester but studied really hard for the exam.  She somehow got the top mark in the class.

ELEPHANT IN THE ROOM

* This is one of my favorite English expressions. I think this idea can be applied to all cultures and used in many situations.
The “Elephant in the room” is an expression that refers to something people don’t want to talk about but everyone is aware of. The “elephant in the room” is often a sensitive or embarrassing topic. People often don’t want to mention it but it is usually something that should be discussed. I’ll give a few examples to make you understand more clearly.
EXAMPLE: We all know that our company is losing money and we might lose our jobs. We have to stop pretending that things are going well and face the problem. We need to talk about the elephant in the room.