5 syllables: de, le, te, ri, ous. Stress on te.
del-uh-TIR-ee-uhs
/ˌdɛləˈtɪɹiəs/
deleterious is pronounced del-uh-TIR-ee-uhs (/ˌdɛləˈtɪɹiəs/). It has five syllables (de-le-te-ri-ous), with the stress on "te". Deleterious means causing harm or damage; harmful or injurious, often describing effects rather than intent. Used in formal, scientific, or literary contexts to indicate negative impact on health, well-being, or success. The term suggests a detrimental consequence rather than mere imperfection, and it is less common in casual speech.
Deleterious means causing harm or damage; harmful or injurious, often describing effects rather than intent. Used in formal, scientific, or literary contexts to indicate negative impact on health, well-being, or success. The term suggests a detrimental consequence rather than mere imperfection, and it is less common in casual speech.
- Systematic misplacement of primary stress; you’ll often hear DE-le-TE-rious or dele-TE-rious. Ensure the main stress lands on the /ˈtɪər/ syllable (third syllable in four-syllable word). - Under-articulation of /ɪə/ combination in the middle; treat it as a two-part vowel /ɪə/ rather than a simple /i/ or /e/. - Final /əs/ can be reduced to /əs/ in fast speech; practice keeping the final syllable clear, especially in formal contexts.
" Exposure to high levels of pollution can have deleterious effects on respiratory health."
" The committee warned that the policy could be deleterious to minority communities."
" Replacing a proven, well-tested approach with a deleterious shortcut often undermines long-term outcomes."
US: /ˌdɛlɪˈtɪəriəs/; UK/AU: /ˌdɛlɪˈtɪərɪəs/. Start with /ˌdɛlɪ/ (DEl-i) then primary stress on /ˈtɪəri/ (TEER-ee) followed by /əs/. Visualize de-LEH-teh-ree-uhs with emphasis on TEER. Tip: keep the /ɪə/ as a smooth center vowel sequence rather than a crisp split.
Common errors: (1) Stress on the first syllable: de-LE-terious; correct is de-LE-terious with primary stress on the third/second-to-last syllable. (2) Slurring /ɪə/ into a simple /i/ or /e/: pronounce /ɪɛə/ as a quick, two-part vowel; aim for a genuine /ɪə/ transition. (3) Dropping the final /əs/ or mispronouncing /t/ as a flap; keep /tɪəriəs/ with a clear /t/ before /iː/.
US: primary stress on the third syllable; rhotic r often pronounced; /ˌdɛlɪˈtɪəriəs/. UK/AU: similar rhythm but with a slightly longer /ɪə/ in the /tɪə/ sequence and non-rhoticity can reduce rhotic r in some dialects; /ˌdɛlɪˈtɪərɪəs/. Accent can affect the quality of the /ə/ in -ous ending; Australians might have a relatively clipped final /əs/.
The challenges include: (1) a four-syllable structure with a heavy stressed unit on the mid-late syllable; (2) the diphthong /ɪə/ in the middle of the word and the /ɜː/ or /ɪə/ glide in some accents; (3) the final '-ous' cluster often reduced in casual speech but must be clearly articulated in careful speech. Focus on maintaining the /t/ before the long /iː/ or /ɪə/ and the clear /əs/ ending.
A unique point is the artificial combination of a root meaning harm (del-) with a suffix that conveys quality (-ious). The word encodes evaluated harm rather than immediate, tangible harm; it’s often used to discuss effects or influences that are harmful. Be mindful of not pronouncing it like 'del-EE-ter-ious' with a stress on -EE-; the natural pattern places emphasis on -tɪər- or -tɪəri-.
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- US: rhotic, larger emphasis on /ˈtɪəri/; pronouncing /ɪə/ as a clear, mid-diphthong helps natural flow. - UK: less rhotic in some varieties; keep the /ˈtɪə/ portion crisp and avoid turning it into /tɪə/ or /tiːə/. - AU: tends to be a clipped vowel length; maintain the /ɪə/ glide and ensure the final /əs/ is audible in careful speech. IPA references: US /ˌdɛlɪˈtɪəriəs/, UK /ˌdɛlɪˈtɪərɪəs/, AU /ˌdɛlɪˈtɪəriəs/.
The word deleterious comes from Middle English deleterius, borrowed from Latin deleterius, from delēter, dele- 'to harm, injure' + -ius. The root del- traces to Latin deleō, delēre ‘to erase, destroy,’ via the sense of causing ruin. In Latin, deleterius carried the sense of destructive, injurious. The English adoption solidified in the 17th century, initially in scientific and medical discourse to describe harmful effects or agents. Its usage matured as an evaluative adjective, often paired with nouns like effects, consequences, or influences. Etymologically, deleterious aligns with a family of -ous adjectives formed from Latin stems indicating quality or relation. The semantic shift centered on association with negative impact on health, safety, or welfare, rather than mere imperfection. The word gained traction in discussions of medicine, biology, and public policy where language required precise assessment of risk. First known uses appear in medical and scientific texts penned in the early modern period, with broader literary adoption in subsequent centuries as scientific rhetoric permeated general discourse.
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Words that rhyme with "deleterious"
-ous sounds
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