per·tur·ba·tion 
/ˌpɚtɚˈbeɪʃən/ noun
plural per·tur·ba·tions /ˌpɚtɚˈbeɪʃən/ noun 1 technical : a change in the normal state or regular movement of something [count] ▪ a perturbation in the planet's orbit [noncount] ▪ gravitational perturbation 2 [noncount] formal : the state of being worried or upset
▪ mental/emotional perturbation
▪ mental/emotional perturbation
