# efficient

/ɪˈfɪʃənt/ (US) · /ɪfˈɪʃənt/ (UK)

Source: https://englishreference.com/word/efficient
Updated: 2026-06-19

## Senses

### 1. productive and organized

adjective · CEFR B2

working in a well-organized way without wasting time or energy.

For teachers: performing or functioning in the best possible manner with the least waste of time and effort.

- The new secretary is very efficient and finishes her reports much faster than the last one.
- By reorganising the workflow, the manager created a more efficient system that reduced overtime costs by twenty percent.

### 2. energy or resource usage

adjective · CEFR B2 · Technical

using very little fuel, electricity, or money to do a job.

For teachers: relating to the ratio of useful output to the total energy or resources consumed.

- We bought an efficient washing machine that uses less water and electricity.
- The engineering team focused on developing a more fuel-efficient engine to meet the new environmental regulations.

### 3. causing an effect

adjective · CEFR C2 · Formal · Technical

the actual thing or person that makes something happen.

For teachers: acting as the immediate agent or cause that produces a specific effect or result.

- The court had to decide if the driver's actions were the efficient cause of the accident.
- In legal theory, the efficient cause is the primary agency that sets a chain of events in motion, leading directly to the injury in question.

Usage: Commonly found in the phrase 'efficient cause' in legal or philosophical texts.

## Examples

- The new heating system is much more efficient.
- The manager introduced an efficient new filing system that reduced the time spent on paperwork by half.
- Modern logistics companies rely on highly efficient algorithms to determine the most fuel-effective routes, ensuring that thousands of packages reach their destinations with minimal environmental impact.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.