日語 Japanese Ask Questions Thread2 質問

If you have a question about the language, ask it and fellow 4channers might see it and answer it for you.

Japanese - Ask questions thread
http://dis.4chan.org/read/lang/1174719097/l50

かぎをかける　means to lock the door or literally turn the key, I believe. So, "I couldn't remember whether I locked the door" kakeru has loads of definitions.

Can anyone tell me what マジ受ける　means? ukeru again has loads of definitions. Context is that this girl says it in response to some things that I say.