Skewed gate
Beginner
A gate deliberately built so one kind of output change (up or down) happens faster than the other.
Novice
A gate whose PMOS and NMOS are sized unequally on purpose, which moves its switching threshold away from the middle and makes one edge faster at the expense of the other.
Expert
Beta ratio (relative to the balanced point). High-skew gates favor the rising output, low-skew the falling one; the cost is a smaller noise margin on one side and a slower opposite edge. Used on critical edges in pulsed and domino-style paths.