Dictionary/活性かっせいKassei活性 (Kassei) is a Japanese noun meaning “activity, active”.MeaningsnounactivityprenominalactiveKanji in 活性活lively性sexRelated words生きるto live女性woman男性man生けるto arrange (flowers)可能性possibility生活life性nature (of a person)活動activity (of a person, organization, animal, volcano, etc.)性格character (of a person)生かすto make (the best) use of活躍activity (esp. energetic or successful)可能性が高いvery likely