i-adjective
whitish; pale white
Describes something that is faintly or slightly white, often with a nuance of being dull or lacking brightness.
空が薄白くなってきた。
The sky has become whitish.
彼は薄白いシャツを着ていた。
He was wearing a pale white shirt.
白い means 'white' in a clear, pure sense, while 薄白い means 'whitish' or 'pale white', indicating a weaker or duller white.
Compound of 薄 (usu, 'thin, faint') + 白い (shiroi, 'white'). The reading うすじろい reflects rendaku voicing of しろい to じろい.