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# reactive

«reactive» in Mova's school dictionary: **Likely to change quickly when it meets another substance…** — its meaning for a pupil, its sense in the lessons and examples.

### part of speech

adjective (reactive, more reactive, most reactive)

### meaning for a pupil

1) (science) Likely to change quickly when it meets another substance; a reactive metal like sodium reacts strongly with water. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#m1)

2) Acting only after something has happened, instead of planning ahead (the opposite of "proactive"). [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#m2)

3) Easily upset or quick to respond strongly to things, like a reactive dog that barks at everything. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#m3)

### sense in the lessons

In science lessons, the reactivity series lists metals from most reactive (potassium, sodium) to least reactive (gold, platinum) — gold stays shiny because it is not reactive. In everyday life, a reactive person or team waits for problems and then fixes them, while a proactive one prevents them. Phrases: highly reactive, reactive metal, reactive to light, reactive rather than proactive.

### examples

- Sodium is so reactive that it fizzes and bursts into flame in water. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x1)
- Gold is not very reactive, so it does not rust. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x2)
- Our dog is reactive and barks at every bike. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x3)
- Don't just be reactive — plan ahead before problems happen. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x4)
- Some sunglasses are reactive to light and darken in the sun. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x5)
- Potassium is more reactive than iron. [tree →](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/#x6)

### note

Opposite in science: unreactive or inert. Opposite in behaviour: proactive. Noun: reactivity (science) or reaction. Do not confuse "reactive" (likely to react) with "radioactive" (giving off radiation).

### Trees and pragmatics

[Every meaning and example of «reactive» parsed by Mova](https://md.mova.elamur.ai/free/en/corpora/dictionaries/school/R/reactive/), each sentence with its dependency tree and frames.