turbid (adj.)

late 13c. distourben, "to frighten, alarm, break up the tranquility of;" c. 1300, "to stop or hinder;" from Old French destorber (Old North French distourber) and directly from Latin disturbare "throw into disorder," from dis- "completely" (see dis-) + turbare "to disorder, disturb," from turba "turmoil" (see turbid). Related: Disturbed; disturbing; disturbingly.

Middle English also had the verb as distourblen, from Old French destorbler; hence also distourbler (n.) "one who disturbs or incites" (late 14c.).

late 13c., "mental distress, emotional disorder of the mind, grief," from Old French destorbance (12c., Old North French distorbance), from destourber, from Latin disturbare "throw into disorder," from dis- "completely" (see dis-) + turbare "to disorder, disturb," from turba "turmoil" (see turbid).

Meaning "public disturbance, political agitation" is from c. 1300; that of "violent interruption of peace or unity" is late 14c.; it is the sense in disturbance of the (king's) peace," early 15c.