perturbation

/ˈpʌrdərˌbeɪʃən/

Other forms: perturbations

When you're on an airplane with your friend who's terrified of flying, you'll be able to sense her perturbation, even if she doesn't say a word about how scared she is. The noun perturbation means "anxiety or uneasiness."

Perturbation means "a state of agitation," or it can refer to whatever's causing the anxiety. Your brother's weird haircut could be the perturbation that's upsetting your mom at Thanksgiving dinner. It usually means a personal feeling of upset or nervousness, but perturbation can also be a physical disruption of some kind, like a perturbation in a river that makes the water become choppy and dangerous. In astronomy, perturbation is a change caused by the gravitational pull of a celestial body.

Definitions of perturbation

1. noun

   the act of causing disorder
   synonyms: disruption

   types:

   breakdown, dislocation

   the act of disrupting an established order so it fails to continue

   surprisal, surprise

   the act of surprising someone

   type of:

   disturbance

   the act of disturbing something or someone; setting something in motion
2. noun

   an unhappy and worried mental state
   synonyms: disturbance, upset

   type of:

   agitation

   a mental state of extreme emotional disturbance
3. noun

   a disposition that is confused or nervous and upset
   synonyms: fluster

   type of:

   discomposure

   a temperament that is perturbed and lacking in composure
4. noun

   activity that is a malfunction, intrusion, or interruption
   “the term `distress' connotes some degree of perturbation and emotional upset”

   synonyms: disturbance

   types:

   bother, fuss, hassle, trouble

   an angry disturbance

   magnetic storm

   a sudden disturbance of the earth's magnetic field; caused by emission of particles from the sun

   type of:

   activity

   any specific behavior
5. noun

   (physics) a secondary influence on a system that causes it to deviate slightly
   types:

   variation

   (astronomy) any perturbation of the mean motion or orbit of a planet or satellite (especially a perturbation of the earth's moon)

   libration

   (astronomy) a real or apparent slow oscillation of a moon or satellite

   type of:

   influence

   the effect of one thing (or person) on another