roil

 
Pronunciation: /rɔɪl/

verb

  • 1 [with object] literary make (a liquid) turbid or muddy by disturbing the sediment: winds roil these waters
  • [no object] (of a liquid) move in a turbulent, swirling manner: the sea roiled below her

Origin:

late 16th century: perhaps from Old French ruiler 'mix mortar', from late Latin regulare 'regulate'