# reactive

/ɹiˈæktɪv/ (US) · /ɹɪˈæktɪv/ (UK)

Source: https://englishreference.com/word/reactive
Updated: 2026-06-20

## Senses

### 1. responding to events

adjective · CEFR B2

acting only after something has happened, rather than planning for it before it happens.

For teachers: characterised by a tendency to respond to events after they occur rather than initiating proactive measures.

- The company was too reactive and only fixed the problem after customers complained.
- A reactive management style often leads to crisis-driven decision-making, whereas a proactive approach identifies potential risks before they manifest as systemic failures.

### 2. chemical change

adjective · CEFR C1 · Technical

describing a substance that changes easily when it comes into contact with another substance.

For teachers: readily taking part in chemical reactions; having a high degree of chemical activity.

- Potassium is a highly reactive metal that must be stored in oil.
- The laboratory technician warned that the compound was extremely reactive when exposed to even trace amounts of atmospheric moisture.

### 3. electrical circuits

adjective · CEFR C2 · Technical

related to parts of an electric circuit that store energy instead of just letting it flow through.

For teachers: pertaining to a circuit or component characterised by induction or capacitance rather than pure resistance.

- The engineer measured the reactive power to check the efficiency of the motor.
- In AC power systems, reactive loads can cause the voltage and current to fall out of phase, necessitating the use of capacitors for power factor correction.

## Examples

- She is reactive instead of proactive.
- The team was reactive to the crisis rather than prepared.
- A reactive strategy often leads to higher costs because decisions are made under pressure rather than through careful planning.

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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.