adverb, adverb taking the 'to' particle
Mimetic adverb describing a slow, heavy, or sluggish movement, often with a sense of lack of energy or reluctance. Commonly used with と.
彼はもそりと立ち上がった。
He stood up slowly and sluggishly.
もそりとした動きで、猫がソファから降りた。
With a sluggish movement, the cat got down from the sofa.