worsen

verb3

1. •
   To make worse; to impair.

   • Global warming has worsened the weather.
   • As for further retaliation: adding such fuel to the fire, as it were, will only worsen the already unpleasant state of affairs.
2. •
   To become worse; to get worse.

   • The weather has worsened.
3. •
   (no longer used) To get the better of; to worst.