How to say "swarm" in Japanese

• 群がるむらがるJLPT N1approx.Common
  godan verb, intransitive verbThe verb for swarming or gathering densely — insects clustering round a light, people crowding to a spot. It describes the action of converging, not the group itself.
  群衆ぐんしゅうが現場げんばに群むらがった。↗

  A crowd gathered at the scene.
• たかるCommon
  godan verb, intransitive verbTo swarm or crowd round someone or something — fans mobbing a celebrity, flies converging on food. Often carries a pushy, pestering nuance; usually written in kana alone.
  捨すてられたアイスのまわりにアリがウヨウヨたかっていた。↗

  The area around the melting ice cream was crawling with ants.
• 群れるむれるCommon
  ichidan verb, intransitive verbThe verb for crowding, flocking or swarming together as a group — fish schooling, birds flocking. It pictures a group keeping together as one, rather than converging on a target.
• 群ぐんJLPT N1approx.Common
  noun, noun (suffix)A noun for a group, bunch, crowd or throng — a swarm viewed as one mass, such as a throng of people. It largely overlaps with 群れ, and for many groups either noun will do.
  牧羊犬ぼくようけんが、羊ひつじの群ぐんを牧場ぼくじょうへ連つれていく。↗

  A sheep dog drives the flock to the pasture.
• 群れむれJLPT N2approx.Common
  nounThe noun for a group, crowd, flock or herd — a swarm of insects, a school of fish, a crowd of people. It names the group itself rather than the swarming action.
  鳥とりは群むれをなして飛とんでいた。↗

  The birds were flying in a group.

For the action of swarming choose a verb — 「群がる」 for dense gathering, 「たかる」 for crowding round someone or something, 「群れる」 for flocking together — and for the group itself a noun, 群 or 「群れ」, which overlap heavily.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 群がるむらがるto swarm
• たかるto gather
• 群れるむれるto crowd
• 群ぐんgroup
• 群れむれgroup
• 密集みっしゅうcrowding together
• 蝟集いしゅうswarm
• 雲集うんしゅうswarm
• 群をなすぐんをなすto swarm
• 雪崩を打つなだれをうつto surge like an avalanche
• 群がりむらがりcrowding together
• 雲霞うんかswarm (of people)
• すだくto gather