ぐんぐん

ぐんぐんgungun

adverb

  1. rapidly
  2. vigorously
  3. by leaps and bounds
  4. steadily

Study it in Yanamino

Data from JMdict, KANJIDIC2 (EDRDG), KanjiVG, CC-CEDICT and Make Me a Hanzi. Sources and licences