adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
in swarms; in clusters; crawling with
Describes many small creatures or people gathered in a teeming, wriggling mass. Often used with いる or 集まる.
公園にハトがうじゃうじゃいる。
There are pigeons swarming in the park.
夏になると
In summer, mosquitoes come out in swarms around here.
adverb, adverb taking the 'to' particle, noun or participle which takes 'suru'
tediously; slowly; in a sluggish mass
Rare usage for something moving or progressing in a slow, tedious, or sluggish manner. Not commonly used in modern Japanese; the swarming sense is dominant.
行列がうじゃうじゃと進む。
The line moves forward sluggishly.