adverb taking the 'to' particle, adverb, noun or participle which takes 'suru'
absentmindedly; vacantly; carelessly
Describes a state of being spaced out, not paying attention, or doing something without thinking. Often used with する or と. Cross-referenced with ぼんやり sense 2, which has a similar meaning.
See also: ぼんやり
He was staring vacantly out the window.
うっそりしていて、電車を乗り過ごした。
I was spacing out and missed my train stop.
うっそりと歩いていたら、人にぶつかった。
I bumped into someone while walking absentmindedly.