[ ə(ʊ)'peɪk ]
■ adjective ( ~r , ~st )
1》 not able to be seen through; not transparent.
2》 difficult or impossible to understand.
■ noun an ~ thing.
↘ Photography a substance for producing ~ areas on negatives.
Derivatives
~ly adverb
~ness noun
Origin
ME opake , from L. opacus 'darkened'.