Which term describes a condition or situation that is lacking in easy movement or fluidity?

The term "viscous" aptly describes a condition or situation that is lacking in easy movement or fluidity. Viscosity is a property of fluids that reflects their resistance to deformation and flow. When a substance is viscous, it means that it is thick and sticky, which impedes smooth movement; for instance, honey is more viscous than water, making it flow more slowly and cohesively.

In contrast, other terms present different nuances. "Sticky" suggests a surface adherence that won't necessarily imply overall movement but rather objects sticking together. "Clumsy" refers to a lack of coordination or grace in movement, which may not directly address the physical property of fluidity. "Fluid," on the other hand, denotes ease of movement and adaptability, the opposite of what is being described in the question. Thus, "viscous" is the most accurate term for describing a situation where movement is hindered or not fluid.