opaquer

/OW0 P EY1 K ER0/
adjective
  1. 1

    Neither reflecting nor emitting light.

  2. 2

    Allowing little light to pass through, not translucent or transparent.

  3. 3

    Unclear, unintelligible, hard to get or explain the meaning of

  4. 4

    Obtuse, stupid.

  5. 5

    Describes a type for which higher-level callers have no knowledge of data values or their representations; all operations are carried out by the type's defined abstract operators.

Source: https://en.wiktionary.org/wiki/opaque, https://en.wiktionary.org/wiki/opaquer