Understeer
Understeer is when the front tyres lose grip first and the car runs wide of where the driver is pointing it.
It feels like the car refusing to turn, and the instinctive correction — more steering lock — usually makes it worse, since a tyre already past its limit generates less grip the further it is turned.
It is the safer of the two imbalances and the one teams tend to err towards, because it is predictable. It is also slower: a car that will not rotate has to be driven around the problem.