Is It Meaning

(South Africa, MLE) really? is that so?

Example: Used other than as an idiom: see is,‎ it.
  - It's ten o'clock already.
  - Is it?
  - I'm feeling tired.
  - Is it?
2007, Dan le Sac vs. Scroobius Pip, "Thou Shalt Always Kill" on Angles
  Thou shalt not express your shock at the fact that Sharon got off with Brad at the club last night by saying "is it?"