Detuning = taking a perfectly good pair of carving or racing skis with nice sharp edges and making them blunt skidding skis so that they don't accidently turn on a dime just because you have made the the precise and exact physical movements that should make them turn on a dime.
It's what most shops will do when you bring your race skis in for a tune up
: , because most people who bring their expensive racing skis in to the shop really don't want them to behave like race skis; they only bought them because they were a status symbol.
Some people prefer to skid a bit more on turn entry or exit and tailor the performance by dulling a tiny bit of the tip and tail, making it easier for them to control their turns. Some people want to skid turns and still want a "race" ski because they don't want it falling apart at speed. I can live with that
: , now that I understand.
Just try them sharp first; it's easier to dull them than to sharpen them.