# porous

/ˈpɔɹəs/ (US) · /pˈɔːɹəs/ (UK)

Source: https://englishreference.com/word/porous
Updated: 2026-08-08

## Senses

### 1. allowing liquids/gases to pass

adjective · CEFR B2

having many small holes that let water, air, or other liquids pass through slowly.

For teachers: possessing minute pores or interstices that permit the passage of fluids or gases.

- The soil is very porous, so the rain water drains away quickly.
- Because the limestone is highly porous, the groundwater moves through the rock layers with relative ease, eventually forming underground caverns.

Usage: Usually placed before a noun or after a linking verb like 'is' or 'seems'.

### 2. weak or easy to pass through

adjective · CEFR C1 · Academic

easy to get through because of many gaps or weaknesses.

For teachers: metaphorically describing a boundary, defense, or law that is easily penetrated or bypassed due to gaps or lack of enforcement.

- The country has porous borders that are difficult for the police to watch.
- Critics argued that the new regulations were too porous, allowing large corporations to exploit several legal loopholes to avoid paying taxes.

Teaching tip: This sense is common in political and legal contexts when discussing borders, security, or laws.

## Examples

- Sponges are very porous materials.
- The gardener added sand to the heavy clay soil to make it more porous and improve drainage.
- Geologists analyzed the porous limestone to determine how quickly groundwater could move through the aquifer and reach the local wells.

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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.