Bioinspired propulsion has been actively incorporated into underwater robots in the past decade. The propulsor, such as a pitching/heaving foil, is usually modeled as a rigid body, since it is easier to manufacture, control, and has a higher maintainability and serviceability. The rigid propulsor, however, has a lower thrust as compared to a flexible one. Modifying the motion of a rigid pitching propulsor can enhance the thrust but at the cost of efficiency. A nature-inspired novel pitching (modified) motion is computationally studied to enhance the thrust of a pitching rigid propulsor without deteriorating the propulsion efficiency. The modified motion depends on the parameter 𝕋 (=T₁/T time period ratio), which is studied between range [0.8, 1.2].