'worsen' originates from English, formed by adding the verb-forming suffix '-en' to the adjective 'worse' (comparative of 'bad'/'evil'), where 'worse' meant 'more bad' or 'more severe'.

'worse' comes from Old English 'wyrsa' (comparative form), and in Middle English the verb 'worsen' was formed by adding '-en'; later the gerund/participle 'worsening' developed and the plural 'worsenings' is derived from that.

Initially related to the comparative sense 'more bad' or 'more severe', it evolved into the verb sense 'to make or become worse' and the noun sense 'the process or instance of becoming worse', which is the modern usage.