Physical unclonable functions (PUFs) are of immense potential in authentication applications for numerous Internet of Things (IoT) devices. For creditable and lightweight PUF applications, high reconfigurability, ultra-low power, and large challenge-response pair (CRP) space are highly desirable. Here we report the first demonstration of ferroelectric field-effect transistor (FeFET)-based strong PUF with high reconfigurability and energy efficiency. Unlike prior works, for the first time, we utilize the FeFET cycle-to-cycle variation all around and the unique charge-domain in-memory computing to empower excellent performances. The proposed 2FeFET-1C PUF cell is fabricated using 28nm HKMG technology for verification. Experimental measurements performed on integrated FeFET arrays reveal excellent uniformity, uniqueness, and repeatability. Remarkably, our PUF achieves near-ideal reconfigurability (HDreconfig, 50.02%) and ultra-low 4.014fJ/bit readout energy, significantly outperforming the state-of-the-art designs. Furthermore, we show that the PUF can operate with high robustness and provide almost unpredictable resilience against machine learning (ML) attacks. These superior performances demonstrate the great promise of the first FeFET-based strong PUF in practical IoT edge-side security solutions.