adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
drowsily; nodding off; half-asleep
Describes a state of drifting in and out of sleep, often while sitting or lying down. Commonly used with する or followed by と.
テレビを見ながらうつらうつらしていた。
I was dozing off while watching TV.
うつらうつらと眠りかけたとき、電話が鳴った。
Just as I was nodding off, the phone rang.