This is the 2845th most frequent Japanese word.
うっすら
Faintly or slightly; barely noticeable.
In this sentence, 'うっすら' indicates a slight or gentle appearance of snow, suggesting that it is not heavily accumulated.
うっすらと雪が積もっている。
There is a thin layer of snow covering the ground.
Here, 'うっすら' describes the subtle presence of an emotion, anxiety, which is not overtly expressed but can be slightly noticed.
彼の言葉にはうっすら不安が見えた。
His words subtly revealed anxiety.
In this usage, 'うっすら' refers to the faint visibility of an image, portraying that it is starting to appear but is not yet clear.