head first

Từ điển Oxford Advanced Learner 8th

ˌhead ˈfirst idiom
1. moving forwards or downwards with your head in front of the rest of your body
•He fell head first down the stairs.
2. without thinking carefully about sth before acting
•She got divorced and rushed head first into another marriage.
Syn: ↑headlong
Main entry: ↑head_idiom