effective
effective — adjective
1. bringing about the outcome someone wanted or hoped for, often in practical situa
bringing about the outcome someone wanted or hoped for, often in practical situations where the approach actually works
The new marketing campaign was highly effective, bringing in hundreds of new customers.
collocation: highly effective
Jessica found that a simple checklist was the most effective way to manage her daily tasks.
pattern: effective way to + infinitive
This cleaning spray is effective against grease and oil stains on kitchen surfaces.
Hamza's calm voice was an effective tool for settling arguments among the children.
The company needs a more effective strategy for reaching younger buyers online.
- successful
broader — focuses on achieving a positive outcome, often after effort
- productive
emphasises producing a large amount of output or results
- useful
simpler and less formal; describes something that helps in a practical way
- ineffective
direct opposite — failing to produce the desired result
- useless
stronger and more informal — completely unable to produce any good result
文法句型
effective + noun
effective at/in + noun/gerund
effective against + noun
用法筆記
Frequently modified by adverbs such as 'highly', 'very', 'remarkably', 'equally', 'less', or 'more'. The opposite is 'ineffective'. Do not confuse with 'efficient' — an effective method produces the desired result; an efficient method produces the desired result with the least waste of time or effort.
常見錯誤
2. (of a medical treatment or drug) found to produce good results in ordinary use b
(of a medical treatment or drug) found to produce good results in ordinary use by the general public, not just in strictly controlled lab experiments
Doctors are studying whether this new drug is effective in real-world patients outside of clinical trials.
pattern: effective in + noun phrase (patient group)
The vaccine proved effective among elderly populations in rural parts of the country.
pattern: effective among + population group
The treatment worked well in the lab but was less effective on actual patients with other health conditions.
Obi asked his doctor how effective the new medicine would be for his particular condition.
- efficacious
more formal; means proven to work in controlled scientific tests rather than real-world use
- ineffective
failing to produce the desired medical result in real-world use
文法句型
effective in + noun/gerund
effective among + group
effective for + noun
用法筆記
This sense is primarily used in medical and pharmaceutical contexts. It contrasts with 'efficacious', which means the treatment works under strictly controlled conditions (efficacy). 'Effective' in this sense means it works in real-world use (effectiveness).
3. having a real effect or position in practice, even though this is not the offici
having a real effect or position in practice, even though this is not the official or legal situation
Although Tamar had no official title, she was the effective leader of the entire research team.
pattern: effective + role/title (de facto meaning)
The ceasefire brought an effective end to the fighting, even though no peace treaty was ever signed.
After the founder retired, his daughter became the effective head of the family business without any formal announcement.
The old regulations were never officially removed, but they are no longer effective in practice.
文法句型
effective + noun (role/status/control)
用法筆記
Used only before a noun (attributive position). Common in formal, legal, and political writing. Often interchangeable with the Latin phrase 'de facto', which is used similarly in English.
常見錯誤
4. (of a law, rule, agreement, or official decision) starting to operate legally an
(of a law, rule, agreement, or official decision) starting to operate legally and be put into practice
The new parking regulations become effective on the first of March, so mark your calendar.
collocation: become effective on + date
Padma was told that her health insurance would be effective from the day she submitted the application form.
collocation: effective from + date/event
The court's ruling will remain effective for the next three years unless an appeal changes it.
Once the agreement is signed by both parties, the new terms become immediately effective.
文法句型
become effective
effective from + date
effective on + date
remain effective
immediately effective
用法筆記
Almost always used predicatively (after 'become', 'remain', 'be'). Common in official announcements, contracts, and legal documents. The phrase 'effective immediately' is a fixed expression used in formal notices of policy changes.
常見錯誤
effective — noun
1. a person or thing that is able to produce a desired result, especially in a mili
a person or thing that is able to produce a desired result, especially in a military or organizational context where capable members are counted separately
The general reviewed his troops and counted only three thousand effectives ready for the mission.
military context: count + effectives
The committee needs to identify the effectives in the group — those who can actually get the work done.
Out of fifty volunteers, only twenty were effectives who could be relied upon in an emergency.
During the war, the unit lost half its effectives in the first month of fighting.
- operative
a person who works effectively, especially in military or intelligence contexts
文法句型
the effectives
effective in + noun phrase
用法筆記
Very rare in modern English. Most commonly appears in historical military contexts referring to soldiers available for duty. Learners at CEFR C2 may encounter this in older texts but should generally use 'effective' as an adjective.