plunge into

US /plʌndʒ ˈɪntuː/
UK /plʌndʒ ˈɪntuː/
"plunge into" picture
1.

飛び込む, 没頭する

to suddenly start doing something or become involved in something, often without careful thought

:
He decided to plunge into the new business venture without hesitation.
彼はためらうことなく新しい事業に飛び込むことを決めた。
After graduation, she will plunge into a demanding career.
卒業後、彼女は厳しいキャリアに飛び込むだろう。