Old English fretan "devour, feed upon, consume," from Proto-Germanic compound *fra-etan "to eat up," from *fra- "completely" (from PIE root *per- (1) "forward," hence "through") + *etan "to eat" (from PIE root *ed- "to eat"). Cognates include Dutch vreten, Old High German frezzan, German fressen, Gothic fraitan.
Used of monsters and Vikings; in Middle English used of animals' eating. Notion of "wear away by rubbing or scraping" (c. 1200) might have come to this word by sound-association with Anglo-French forms of Old French froter "to rub, wipe; beat, thrash," which is from Latin fricare "to rub" (see friction). Figurative use is from c. 1200, of emotions, sins, vices, etc., "to worry, consume, vex" someone or someone's heart or mind, from either the "eating" or the "rubbing" sense. Intransitive sense "be worried, vex oneself" is by 1550s. Modern German still distinguishes essen for humans and fressen for animals. Related: Fretted; fretting. As a noun, early 15c., "a gnawing," also "the wearing effect" of awareness of wrongdoing, fear, etc.
Proto-Indo-European root meaning "to eat," originally "to bite."
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit admi "I eat;" Avestan ad- "to eat;" Greek edo "I eat;" Latin edere "to eat;" Lithuanian ėdu "I eat," ėdžioti "to devour, bite;" Hittite edmi "I eat," adanna "food;" Armenian utem "I eat;" Old Church Slavonic jasti "to eat," Russian jest "to eat;" Old Irish ithim "I eat;" Gothic itan, Old Swedish and Old English etan, Old High German essan "to eat."
Proto-Indo-European root forming prepositions, etc., meaning "forward," and, by extension, "in front of, before, first, chief, toward, near, against," etc.
It forms all or part of: afford; approach; appropriate; approve; approximate; barbican; before; deprive; expropriate; far; first; for; for-; fore; fore-; forefather; foremost; former (adj.); forth; frame; frau; fret; Freya; fro; froward; from; furnish; furniture; further; galore; hysteron-proteron; impervious; improbity; impromptu; improve; palfrey; par (prep.); para- (1) "alongside, beyond; altered; contrary; irregular, abnormal;" paradise; pardon; paramount; paramour; parvenu; pellucid; per; per-; percent; percussion; perennial; perestroika; perfect; perfidy; perform; perfume; perfunctory; perhaps; peri-; perish; perjury; permanent; permeate; permit; pernicious; perpendicular; perpetual; perplex; persecute; persevere; perspective; perspire; persuasion; pertain; peruse; pervade; pervert; pierce; portray; postprandial; prae-; Prakrit; pre-; premier; presbyter; Presbyterian; preterite; pride; priest; primal; primary; primate; primavera; prime; primeval; primitive; primo; primogenitor; primogeniture; primordial; primus; prince; principal; principle; prior; pristine; private; privilege; privy; pro (n.2) "a consideration or argument in favor;" pro-; probably; probe; probity; problem; proceed; proclaim; prodigal; produce; profane; profess; profile; profit; profound; profuse; project; promise; prompt; prone; proof; proper; property; propinquity; prophet; prose; prostate; prosthesis; protagonist; Protean; protect; protein; Proterozoic; protest; proto-; protocol; proton; protoplasm; Protozoa; proud; prove; proverb; provide; provoke; prow; prowess; proximate; Purana; purchase; purdah; reciprocal; rapprochement; reproach; reprove; veneer.
It is the hypothetical source of/evidence for its existence is provided by: Sanskrit pari "around, about, through," parah "farther, remote, ulterior," pura "formerly, before," pra- "before, forward, forth;" Avestan pairi- "around," paro "before;" Hittite para "outside of," Greek peri "around, about, near, beyond," pera "across, beyond," paros "before," para "from beside, beyond," pro "before;" Latin pro "before, for, on behalf of, instead of," porro "forward," prae "before," per "through;" Old Church Slavonic pra-dedu "great-grandfather;" Russian pere- "through;" Lithuanian per "through;" Old Irish ire "farther," roar "enough;" Gothic faura "before," Old English fore (prep.) "before, in front of," (adv.) "before, previously," fram "forward, from," feor "to a great distance, long ago;" German vor "before, in front of;" Old Irish air- Gothic fair-, German ver-, Old English fer-, intensive prefixes.
"complainer, nagger," 1960s, from Yiddish, from Slavic words meaning "fret, ache," related to the root of nudnik (q.v.).