Fluoride contamination in groundwater has become a serious environmental and public health concern, especially in developing countries where access to advanced water purification technologies remains limited. Conventional defluoridation techniques such as chemical precipitation, ion exchange, and membrane filtration are effective, but their high cost, energy consumption, and operational complexity restrict their use in rural and low-resource areas. In view of these challenges, the present study explores the use of agricultural waste as a low-cost and sustainable material for fluoride removal from water. A bioadsorbent was prepared from the calyx and pedicel of dried red chilli (Capsicum annuum) through a simple process involving controlled drying at 85–120°C, charring, and grinding to obtain fine particles in the range of 150–250 µm. The prepared material showed a porous structure and a relatively high surface area (111.39 m²/g), which is favorable for adsorption. Batch adsorption experiments were carried out using fluoride-contaminated simulated water to evaluate the removal efficiency under different conditions, including adsorbent dosage and contact time. The results indicated that the bioadsorbent was capable of removing 70–90% of fluoride, with an average reduction of around 80% under optimized conditions, bringing fluoride concentration close to permissible drinking water limits recommended by international standards. The adsorption process was achieved without any chemical treatment, demonstrating the natural adsorption potential of the material. The study highlights the practical value of converting agricultural waste into useful bioadsorbents for water purification while also addressing waste management concerns. Due to its low cost, simple preparation, and environmentally friendly nature, the developed bioadsorbent may be suitable for use in rural and fluoride-affected regions. Overall, the findings support the development of sustainable and locally available defluoridation technologies and encourage the use of agro-waste materials in water treatment applications.