<p>This paper investigates admissible finite-time stability and guaranteed-cost synchronization for a class of nonlinear fractional-order switched singular systems with time-varying delays, where the nonlinear terms depend on delayed states. The novelty of this work is twofold. First, admissible finite-time stability is studied for nonlinear fractional-order switched singular systems, which extends several existing results from the linear setting to the more general nonlinear case. By combining the Laplace transform method with the Lyapunov functional approach, a novel switching strategy is developed to guarantee regularity, impulse-free behavior, and finite-time stability through a convex-cone partition of the stability region. Second, a guaranteed-cost synchronization problem is formulated and solved for this class of systems. In particular, a state-feedback controller is designed to realize admissible finite-time synchronization between two distinct nonlinear fractional-order switched singular systems while ensuring an explicit upper bound on the synchronization cost. Finally, two numerical examples are presented to verify the effectiveness of the proposed approach.</p>