Standard Lemma guide

deleterious

adj · 3 senses · updated from the 2026-07-25 local source snapshot

Definitions and examples are grouped by meaning. Pronunciation, history, word forms, translations, descendants, synonyms, antonyms, derived terms, and related words appear whenever the source provides them.

Sound

Pronunciation

Each Play button uses your device's default local English voice, or a natural local fallback. The selected voice name appears after playback. This is synthesized speech, not a source recording.

  • Received-Pronunciation: /ˌdɛl.ɪˈtɪə̯.ɹi.əs/
  • Received-Pronunciation: /ˌdɪl.ɪˈtɪə̯.ɹi.əs/
  • US: /ˌdɛ.ləˈtɪɹ.i.əs/
  • US: Recorded audio is listed in the source snapshot.
  • Australia: Recorded audio is listed in the source snapshot.
  • rhymes with -ɪəɹiəs
  • CMU ARPABET: D EH2 L AH0 T IH1 R IY0 AH0 S Digits mark lexical stress: 1 primary, 2 secondary, 0 unstressed.

1

adj

Meaning 1

Harmful, often in a subtle or unexpected way.

Definition source: English Wiktionary via Wiktextract

Usage: formal

Examples

  • deleterious effects
  • deleterious to someone's health

Meaning relationships

Synonyms: destructive, harmful, hurtful, injurious, noxious, pernicious, damaging, deleterious, detrimental, inimical, mischievous, nocent, nocuous, noisome, prejudicial, scathand, scathel, sullen, venom

Antonyms: none provided

2

adj

Meaning 2

Having lower fitness.

Definition source: English Wiktionary via Wiktextract

Topics: biology, genetics, medicine, natural-sciences, sciences

Examples

  • A deleterious mutation

Meaning relationships

Synonyms: none provided

Antonyms: none provided

3

adjective satellite

Meaning 3

harmful to living things

Definition source: Princeton WordNet 3.0

Examples

  • deleterious chemical additives

Meaning relationships

Synonyms: hurtful, injurious

Antonyms: none provided

History

Etymology

Adapted borrowing (1640s; 1582 as deletorious) of New Latin dēlētērius, dēlētōrius + -ous, from Ancient Greek δηλητήριος (dēlētḗrios, “noxious, deleterious”), from δηλητήρ (dēlētḗr, “a destroyer”), from δηλέομαι (dēléomai, “I hurt, damage, spoil, waste”). Not related to delete or deleble. Doublet of deletery.

Across languages

Translations

32 source translations are retained for this English entry.

  • Belarusian: шкоднасны (škódnasny) — harmful
  • Bulgarian: вреден (vreden) — harmful
  • Catalan: deleteri — harmful
  • Dutch: schadelijk — harmful
  • Faroese: skaðiligur — harmful
  • Finnish: haitallinen — harmful
  • Finnish: epäsuotuisa — harmful
  • Finnish: vahingollinen — harmful
  • French: délétère — harmful
  • German: schädlich — harmful
  • German: gesundheitsschädlich — harmful
  • Greek: βλαπτικός (vlaptikós) — harmful
  • Italian: deleterio — harmful
  • Korean: 해로운 (haeroun) — harmful
  • Norwegian Bokmål: skadelig — harmful
  • Norwegian Bokmål: ødeleggende — harmful
  • Plautdietsch: schätlich — harmful
  • Polish: szkodliwy — harmful
  • Portuguese: deletério — harmful
  • Romanian: deleter — harmful
  • Romanian: vătămător — harmful
  • Romanian: nociv — harmful
  • Romanian: dăunător — harmful
  • Russian: вре́дный (vrédnyj) — harmful
  • Russian: вредоно́сный (vredonósnyj) — harmful
  • Scottish Gaelic: sgriosail — harmful
  • Spanish: deletéreo — harmful
  • Swedish: menlig — harmful
  • Turkish: olumsuz — harmful
  • Turkish: zararlı — harmful
  • Ukrainian: шкідли́вий (škidlývyj) — harmful
  • Ukrainian: згу́бний (zhúbnyj) — harmful