츤데레 (ツンデレ / Tsundere)

 츤데레 (ツンデレ / Tsundere)  This term is often used to describe people who are strict with the people they love, but are actually full of love for them on the inside. Most of the time, it's used for romantic relationships.

It's a word originally used in Japan, it became popular in Korea as well, 

in Korea & Jp, there are so many Dere Series. 

다루데레

메가데레

보코데레

빈데레

얀데레

욕데레

츤데레

쿨데레

Tsuntsun: Short for Tsun Tsun, tsuntsun is an expression that describes acting coldly or showing a cold, blunt, or nervous demeanor. 

Dere : deredere is short for deredere, and is said to show a fond and shy attitude.