開弓沒有回頭箭 [开－没－－头－]

Jyutping hoi1 gung1 mut6 jau5 wui4 tau4 zin3
Pinyin kāi gōng méi yǒu huí tóu jiàn

Definitions (CC-CEDICT)
  1. lit. once you've shot the arrow, there's no getting it back (idiom)
  2. fig. once you started sth, there's no turning back
  3. to have to finish what one started
  4. to be determined to reach one's goals in spite of setbacks
Definitions (Wiktionary)
  1. proverb
    there's no turning back after you make an important decision