adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
Describes large, slow, rhythmic swaying or shaking, often of trees, boats, or heavy objects. Onomatopoeic.
大きな船が波でゆさゆさと揺れていた。
The large ship was swaying slowly on the waves.
地震で家がゆさゆさ揺れた。
The house shook with a slow, heavy motion during the earthquake.