In physics, "underdamped" refers to a type of oscillatory motion where a system oscillates with decreasing amplitude over time but does not come to rest immediately. This behavior is commonly observed in systems like mass-spring systems or electrical circuits when the damping force is relatively low compared to the restoring force. In an underdamped system, the oscillations can continue for several cycles before the energy dissipates significantly. The system takes longer to settle down compared to overdamped systems, which return to equilibrium without oscillating, and critically damped systems, which return to equilibrium as quickly as possible without oscillating.