appatakkar

This term was used in Tamil Cinema for the first time in the movie 'Boss Engira Baskaran' by tamil comedian Santhanam.

Since then, it has shot up in popularity and usage in several tamil conversations and also lot of tam-eng mixed dialogues.

It is a term used to (more often sarcastically) refer to a person as a big shot. More often, this is used in a response statement to someone bragging about himself.