Most semiopaque refers to something that is somewhat transparent but not completely. Antonyms for this word would include "completely transparent," "clear," "crystal clear," "transparent," "diaphanous" and "see-through." These words all describe something that can be seen through easily, without any obstruction. On the other hand, antonyms for semiopaque also include words like "opaque," "nontransparent," "muddy," "murky," and "obscure." These words denote something that completely obstructs the view, making it impossible to see through. It is essential to understand the antonyms and synonyms of words used in writing to convey the intended message clearly.