An Etymological Dictionary of the German Language/Annotated/behagen
behagen, verb (to which behaglich is allied), ‘to be comfortable,’ from the equivalent Middle High German behagen; Old Saxon bilagôn, Anglo-Saxon onhagian, ‘to suit, please,’ Old Icelandic haga, ‘to arrange.’ Old German has only a strong participle, Old High German bihagan, Middle High German behagen, ‘fresh, joyous, comfortable’ (hence Modern High German das Behagen, Unbehagen); the old strong verb no longer exists in Teutonic. Probably the Indian root çak is primitively related to it — çaknômi, ‘am strong, able, helpful, beneficial,’ çakrá-s, ‘strong’; compare further Hag, Hecke, and hegen, which with the same phonetic form approximate the earlier meaning ‘to help, protect.’