'angering' is the present participle of 'anger', which originates from Old Norse, specifically the word 'angr', where 'angr' meant 'grief, sorrow, distress'.

'angr' changed into Old French 'angre' and then into Middle English 'anger', eventually becoming the modern English word 'anger', from which 'angering' is derived as a present participle.

Initially, it meant 'grief or sorrow', but over time it evolved into its current meaning of 'to make someone angry'.