expression, godan verb (-ru), intransitive verb
get into; become passionate about; get fired up
Describes becoming emotionally invested or enthusiastic about an activity, topic, or pursuit. Often used when someone starts putting real energy into something.
最近、彼は料理に熱が入っている。
Lately, he's been really getting into cooking.
As the match approaches, the players have become more fired up in their practice.