noun, takes genitive case の, adjectival noun or quasi-adjective

Usu. 本気で.
  1. seriousness, earnestness, truth, sanctity.

Variations

Pronunciation Kanji Kana Is Common
本気 ほんき

Contained Kanji Breakdown

book, present, main
ホン もと まと (1st, N5)
tree, wood
き モク こ- (1st, N5)
spirit, mind, air
キ き ケ (1st, N5)
spirit, steam radical (no. 84)
キ ケ いき (Kentei 1)
person(人) variant
one, one radical (no.1)
イチ いっ ひと- (1st, N5)
mow, cut grass, subdue
ガイ ゲ おさ.める (Kentei 1)