deleterious - Master This Word
Master this word with our 5-step learning method – Learn English in English
deleterious Word Meanings
- causing harm or damage
- having a negative effect
- injurious to health or well-being
deleterious Example Sentences
Example sentences are the start of understanding. Don't rush to memorize. First feel how the word works in a sentence.
deleterious Phonetic & Pronunciation
UK
/ˌdɛlɪˈtɪəriəs/
US
/ˌdɛləˈtɪriəs/
deleterious Word Etymology
de- (from) + let (to harm) + -ious (pertaining to). Origin: Latin → Old French → English. Imagine a toxic substance leaking, harming everything it touches.
Note 1: These definitions and etymologies are not standard dictionary definitions, but extended explanations provided to help with memorization and understanding of the actual application of words. Through this background information, we strive to make words more vivid and easier to understand, and help you remember their meanings in real life.
Note 2: LexiTalk designs the learning flow around the linguistics principle of “Comprehensible Input.” When learners encounter material that is slightly above their level but still understandable from context, the brain naturally absorbs the language. That’s why we keep every word inside authentic contexts, using examples and associations to help you understand it and use it flexibly.
Read the FAQ explanation of Comprehensible InputReal Context
Deleterious describes something that causes harm, damage, or a negative effect, especially over time. In everyday English, it is often used for substances, policies, or conditions that unintentionally undermine health, safety, or well-being. Learners frequently confuse it with similar words like detrimental, harmful, or injurious; the nuance is stronger and slightly more formal, and is common in scientific, medical, or policy discourse. Remember that deleterious emphasizes damaging consequences rather than just being mildly unfriendly, and it is typically followed by to- or for- phrases, as in deleterious to health or deleterious for the environment.
Usage Reminders
- Deleterious is formal; use it in removal or risk contexts.
- Usually followed by to health or for the environment.
- More formal than harmful or damaging.
- Common in science, medicine, and policy writing.
- Pair with precise nouns like substance, policy, or condition.
Common Misconceptions
- It only refers to physical harm, not policies or practices.
- It is interchangeable with harmful in casual speech.
- It always implies immediate danger, not long-term effects.
- It cannot describe people or living beings.
- It is often used with 'to' or 'for' - remember the common collocations.
Thinking Differences
In English, deleterious sounds formal and science-oriented; it often appears in policy, medical, or environmental discussions. Learners tend to over-extend it to any mild harm, or replace it with casual words like harmful. The key is to reserve it for clear, long-term negative effects and to pair with to/for for precise subjects.
Learning Tips
- Practice formal contexts (science, policy) to feel the nuance.
- Pair with to health or for the environment for collocation.
- Differentiate from harmful and damaging by tone and formality.
- Use specific nouns (substance, policy, condition) after deleterious.
- Read academic passages to see natural usage.
- Check prepositional patterns to avoid awkward phrasing.
5-Step Learning Method - Learn English in English
Step 1: Meaning
What is the meaning of 'deleterious'?
A.Harmful
B.Beautiful
C.Friendly
D.Useful
Step 2: Usage
Which of the following sentences uses 'deleterious' correctly?
A.The puppy's playful behavior was deleterious to the family.
B.She found the new medication to be deleterious to her health.
C.He enjoyed the deleterious weather at the beach.
D.The teacher praised the students for their deleterious efforts.
Step 3: Similar Words
What is a synonym for 'deleterious'?
A.Benevolent
B.Advantageous
C.Positive
D.Detrimental
Step 4: Opposite Words
What is an antonym for 'deleterious'?
A.Beneficial
B.Tolerant
C.Constructive
D.Harmless
Step 5: Mastery
In what real-life context would you expect to encounter the term 'deleterious'?
A.A cooking show presenting a new recipe
B.A gardening class learning about plant care
C.A travel blog describing beautiful landscapes
D.Medical research on the effects of a certain drug
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