noun
kickoff
Used in sports (soccer, American football, etc.) for the start or restart of play, and metaphorically for the start of a project or event.
試合は午後3時にキックオフです。
The match kicks off at 3 p.m.
新プロジェクトのキックオフミーティングは来週です。
The kickoff meeting for the new project is next week.
開始 is a general native-Japanese word for 'start' or 'beginning', while キックオフ is a loanword specifically from sports, often used metaphorically for energetic starts.
Loanword from English 'kickoff'.