Gross Written Premium (GWP) — the total premium (direct and assumed) written by an insurer before deductions for reinsurance and ceding commissions. Find out what is the full meaning of GWP on Abbreviations. GWP means Gift with Purchase. From Wikipedia, the free encyclopedia. [USPRwire, Tue Jul 23 2019] The heating, ventilating, air-conditioning and refrigeration (HVACR) industry is making the steady shift towards low GWP refrigerants,.