뻥 is an informal word for lie, and it also means 'hot air'.
When someone says "뻥치시네", it means "Not falling for that one" or "You must be lying". 뻥 doesn't sound serious as much as 거짓말.
Another one is 구라, it's a slang word. It's said a lot especially in 경상도. 구라 collocates with 치다 like 뻥 does. Either of them sounds really informal when used with 까다.