perturb

verb

Etymology: From Late Middle English perturben (“to disturb (someone) mentally, disquiet; to cause disorder to (something), confuse; to hinder (something)”), from Old French perturber, and from its etymon Latin perturbāre, the present active infinitive of perturbō (“to confuse; to alarm, disturb, trouble, perturb”), from per- (intensifying prefix) + turbō (“to agitate, disturb, unsettle, perturb; to upset”) (from turba (“disorder, disturbance, turmoil”) (possibly from Ancient Greek τῠ́ρβη (tŭ́rbē, “confusion, disorder, tumult”), either from Pre-Greek, or Proto-Indo-European *(s)twerH- (“to agitate, stir up; to urge on, propel”)) + -ō (suffix forming infinitives of regular first-conjugation verbs)).

1. To cause (something) to be physically disordered or disturbed; to cause confusion.

   “Mary therefore the more knaue art thou I ſay / That perturbeſt the worde of god I ſay […]”

   “The Nobles ſtandyng by hearyng him thus ſpeake were greatly agreeued with him, notyng in him arrogancy and wilfulneſſe, in perturbyng and refuſyng ſuch an honeſt order of agreement: […]”

2. To disturb (someone, their mind, etc.) mentally; to bother, trouble, upset.

   “[…] I have often found / The truth thereof, in my private paſſions: / For I doe never feele my ſelfe perturb'd / VVith any generall vvords 'gainſt my profeſſion, / They doe avvake, and ſtirre me: […]”

   “He remembered how, […] his childish imagination was perturbed at a phenomenon, for which he could not account.”

3. Of a celestial body: to modify the motion or orbit of (another celestial body) by exerting a gravitational force; hence (physics), to slightly modify (the motion of an object).
4. To slightly modify (a set of equations or their solutions), producing deviations from a simple, easily solvable problem, in order to find an approximate solution to a problem that is more difficult to solve or otherwise unsolvable.
5. To influence (a process or system) so that it deviates from its normal state.
6. To bother, to disturb, to trouble.

   “Thy ghoſt O father ſweete, thy greuous ghoſt, / Perturbing in my dremes hath me compeld to ſee this coaſt.”

   “This growth original of virgin soil, / By fascination felt in opposites, / Pleases and shocks, entices and perturbs.”