ROIL ~ SOIL = muddy
Stir the Oil with Rock.i.e make it murky
Fire in oil company roiled(agitated) the situation
The ROYAL knights are always making war, causing terrible disturbances.
roil = r + oil..consider only the oil part..imagine there is oil in the glass of water which u were going to drink..Sb has added oil kind of thing in ur water to make it turbid