to alter from a settled state; cause to be no longer firmly fixed or established; render unstable; disturb

Violence unsettled the government.

to shake or weaken (beliefs, feelings, etc.); cause doubt or uncertainty about

doubts unsettling his religious convictions.

to vex or agitate the mind or emotions of; upset; discompose

The quarrel unsettled her.

to become unfixed or disordered.

adjective

disquieting , disruptive , distressful , distressing , intrusive , perturbing , troublesome , troublous , upsetting , worrisome