[ hap]
This verb is derived from the past participle of the Latin deponent verb pati: ‘to undergo (a process), to experience (a condition); to be affected, be acted upon’. Pati also developed into the verb patir which can be found in OF: pader Gdf 5,683c; patir 10,297b; TL pader 7,9; DMF pâtir; TLF pâtir; with the more expected form of pati as the past participle. Patir is not attested in Anglo-Norman.