In the senses of “overcrowd (a place)” and “impede (a person)”: from Middle French and Old French empestrer (“encumber”), influenced by English pest. The modern sense is an extension of the sense “infest”. Comparable to English construction pest + -er (used to form frequentative verbs).
Meanings
A bother or nuisance.
By now I presumed I had become a real pester. 2017, Samuel J. Archer, Will There Be Another Lincoln, Nixon, Johnson or Kennedy?, page 15:
In the senses of “overcrowd (a place)” and “impede (a person)”: from Middle French and Old French empestrer (“encumber”), influenced by English pest. The modern sense is an extension of the sense “infest”. Comparable to English construction pest + -er (used to form frequentative verbs).
Meanings
(transitive) To bother, harass, or annoy persistently.
He pestered me with questions.
She pestered him to help her.
(intransitive, obsolete, transitive) To crowd together thickly.
That which eſpecialleſt nouriſht the moſt prime pleaſure in me, was after a ſtorme when they were driuen inſwarmes, and lay close peſtred together as thicke as they could packe; the next day following, if it were faire, they would cloud the whole skie with canuas, by ſpreading their drabled ſailes in the full clue abroad a drying, and make a brauer ſhew with them, then ſo many banners and ſtreamers diſplayed againſt the Sunne on a mountaine top. 1599, [Thomas] Nashe, Nashes Lenten Stuffe, […], London: […] [Thomas Judson and Valentine Simmes] for N[icholas] L[ing] and C[uthbert] B[urby] […], →OCLC, pages 5–6: