constness

const (“a keyword for constant in the C programming language and its derivatives”) +‎ -ness

constness (uncountable)

1. (programming) The declaration of variables or objects as immutable.
   • 1995, Embedded Systems Programming (volume 8, page 180)

     If you want to change a class member inside a const member function, the traditional approach is to cast away constness by saying (X*)this.

• const correctness