Impermeable
/ˌɪmpərˈmiːəbəl/
adjectiveB2
Definition
Impermeable describes a material or surface that does not let liquids or gases go through it. For example, a raincoat is impermeable because water cannot pass through it and make you wet. This word is often used in science, construction, and everyday life when talking about barriers against water or air.
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See It in Action
Not allowing liquids or gases to pass through
- •The raincoat is impermeable to water, so you stay dry.
- •The soil in this area is impermeable, so rainwater cannot go into the ground easily.
- •This plastic container is impermeable, keeping the food fresh by blocking air.
Figurative use: not able to be affected or changed by something
- •He was impermeable to criticism and kept working hard.
- •Her mind was impermeable to bad news that day.
Make It Stick
- ✓Think of "impermeable" like "waterproof" (A1 word), but it applies to liquids and gases, not just water.
- ✓Picture a plastic bag holding water without any drops leaking out.
- ✓It's the feeling of staying dry inside your raincoat even when it is raining hard.
- ✓Sounds like "im-per-mee-uh-bul" → imagine a wall that says "I'M PERMEABLE? NO!" blocking all water and air.
- ✓Imagine stories about spacesuits or submarines that keep air inside and water outside—both need to be impermeable.
- ✓NOT like "porous" (which lets water or air through); impermeable stops everything from passing.
- ✓NOT like "absorbent" (which soaks up liquids); impermeable does not soak or take in anything.
- ✓NOT like "leaky" (which allows things to pass through); impermeable means no leaks at all.
Try Other Words
- •Waterproof: does not let water through (Use when talking specifically about water resistance)
- •Sealed: closed tightly so nothing passes through (Use when emphasizing no openings or gaps)
- •Tight: very close or closed, no space for passing (Use in informal contexts about blocking passage)
- •Nonporous: having no tiny holes that let liquid or air through (Use in scientific or technical contexts)
Unboxing
- •Word parts: prefix "im-" (not) + root "permeable" (able to be passed through)
- •Etymology: From Latin "permeare" meaning "to pass through" + suffix "-able" meaning "able to"
- •Historical development: Used in English since the 17th century to describe materials that liquids or gases cannot pass through
- •Modern usage: Commonly used in science, engineering, and everyday language to describe materials that block water, air, or other substances
- •Key insight: The prefix "im-" changes "permeable" (can be passed) to its opposite, meaning "cannot be passed"
Reflect & Connect
•How does knowing about impermeable materials help us in daily life, like choosing clothes or building houses?
•Can you think of situations where being impermeable could be a problem rather than a benefit?
Fill in the blanks
1.The raincoat is impermeable ___ water, so it keeps you dry during storms.
2.Soil that is impermeable ___ rainwater causes water to stay on the surface and may cause flooding.
3.Unlike a sponge, an impermeable material does not ___ any liquid or air through it.
4.When a container is impermeable, it is usually ___ tightly to keep the inside safe.
5.His attitude was impermeable ___ criticism, so he did not change his mind.
6.The plastic wrap is impermeable ___ air, which helps keep food fresh longer.
7.If a jacket is not impermeable, rain will ___ through and make you wet.