1
Core quality
Causing harm, damage, or an undesirable effect.
Example
Extended drought had a deleterious effect on seedling survival.
deleterious
/ˌdeləˈtɪəriəs/ · del-uh-TEER-ee-usadjective
Causing harm, damage, or an undesirable effect.
Use deleterious to express this relationship precisely: causing harm, damage, or an undesirable effect.
What deleterious Really Means
The word becomes easier to use when its closely related senses are separated and compared.
2
Attributive or predicative use
Use this adjective before a suitable noun or after a linking verb such as be or seem.
Example
The policy proved deleterious to small producers.
3
Analytical distinction
Choose it when this exact descriptive quality matters; a related word may overlap without conveying the same trait.
Example
Even low concentrations may have a deleterious impact on aquatic life.
Use deleterious Naturally
Notice how the surrounding noun or clause reveals the exact shade of meaning.
Extended drought had a deleterious effect on seedling survival.
The policy proved deleterious to small producers.
Even low concentrations may have a deleterious impact on aquatic life.
Precision Matters
Deleterious overlaps with several common words, but each carries a different emphasis.
deleterious
vs.Means causing harm, damage, or an undesirable effect.
catastrophic
Means involving sudden, large-scale damage or disastrous consequences.
deleterious
vs.Means causing harm, damage, or an undesirable effect.
innocuous
Means harmless or unlikely to cause offence or damage.
deleterious
vs.Means causing harm, damage, or an undesirable effect.
undermine
Means to weaken, erode, or reduce confidence in something.
deleterious
vs.Means causing harm, damage, or an undesirable effect.
exacerbate
Means to make a problem, condition, or inequality worse.
Test deleterious in Context
The lighting damages or disrupts the insects' ability to navigate.
1
Researchers found that nighttime lighting had a ___ effect on the insects' navigation.