# opaque

/oʊˈpeɪk/ (US) · /əʊpˈeɪk/ (UK)

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

## Senses

### 1. not see-through

adjective · CEFR B2

not letting light through so that you cannot see what is on the other side.

For teachers: impenetrable by light; neither transparent nor translucent.

- The bathroom window is made of opaque glass to protect people's privacy.
- The artist applied several layers of opaque pigment to ensure the underlying sketch was completely obscured from the viewer.

### 2. hard to understand

adjective · CEFR C1 · Academic · Formal

difficult to understand or explain because it is not clear.

For teachers: obscure or unintelligible in meaning; deliberately or naturally difficult to interpret.

- The report was written in such opaque language that nobody knew what the plan was.
- Critics argued that the government's decision-making process remained opaque, despite promises of greater transparency and public oversight.

### 3. hidden data structures

adjective · CEFR C2 · Technical

describes a piece of computer code where you can use it without knowing how it works inside.

For teachers: referring to a data type whose internal representation is hidden from the client, accessible only through defined interfaces.

- The library uses an opaque pointer so that developers don't accidentally change the internal data.
- By using an opaque data type, the API designer ensures that internal structural changes do not break compatibility with third-party integrations.

### 4. to make less clear

verb · CEFR C2 · Formal · Technical

to make something difficult to see through or hard to understand.

For teachers: to render something opaque or less transparent.

- The software allows you to opaque certain parts of the image for security.
- Specialised chemical treatments can be used to opaque the surface of the plastic during the manufacturing process.

## Examples

- The bathroom window is made of opaque glass for privacy.
- The company's hiring process is notoriously opaque, leaving many applicants confused about why they were rejected.
- While the physical properties of the mineral make it entirely opaque, its chemical composition remains a subject of intense debate among geologists who cannot peer inside the crystal structure.

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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.