真面目くさる

まじめくさる, マジメくさるmajimekusaru

godan verb · intransitive

  1. to become extremely serious (in attitude)
  2. to look solemn
  3. to assume a solemn air

Kanji in this word

Study it in Yanamino

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