to bother persistently with petty annoyances; trouble: Don't pester me with your trivial problems.
Obsolete. to overcrowd.
Origin of pester
1530–40; perhaps aphetic variant of empester,impester to tangle, encumber (though pester is found earlier than these 2 words) < Middle Frenchempestrer to hobble, entangle < Vulgar Latin*impāstōriāre to hobble, equivalent to im-im-1 + pāstōri(a) a hobble, noun use of Latinpāstōrius of a herdsman or shepherd + -āre infinitive suffix (see pastor); aphetic form apparently reinforced by pest (cf. -er6)
Related formspes·ter·er, nounpes·ter·ing·ly, adverbpes·ter·some, adjectiveun·pes·tered, adjective
C16: from Old French empestrer to hobble (a horse), from Vulgar Latin impāstōriāre (unattested) to use a hobble, from pāstōria (unattested) a hobble, from Latin pāstōrius relating to a herdsman, from pastor herdsman
1520s, "to clog, entangle, encumber," probably a shortening of Middle French empestrer "place in an embarrassing situation" (Modern French empêtrer, Walloon epasturer), from Vulgar Latin *impastoriare "to hobble" (an animal), from Latin im- "in" + Medieval Latin pastoria (chorda) "(rope) to hobble an animal," from Latin pastoria, fem. of pastorius "of a herdsman," from pastor "herdsman" (see pastor (n.)). Sense of "annoy, trouble" (1560s) is from influence of pest. Related: Pestered; pestering.