subopaque
/ˌsʌbəʊˈpeɪk, -ˌpoʊˈpeɪk/Definitions
1. adjective
Not completely opaque but blocking most light; partially opaque
“The subopaque filter reduced the intensity of the sun’s rays.”
2. noun
A subopaque material or substance
“The subopaque paint applied a thick layer to the wall.”