萬無一失 [万无－－]

Jyutping maan6 mou4 jat1 sat1
Pinyin wàn wú yī shī

Definitions (CC-CEDICT)
  1. surefire; absolutely safe (idiom)
Definitions (粵典–words.hk)
  1. 語句
    絕對​唔​會​失敗​、​犯錯​；​包保​成功​；​實會​掂​過碌蔗
    would not fail under any circumstances; surefire
  2. 語句
    毫無風險​；​絕對​安全
    no risk at all; perfectly safe
    • 帶埋手提電話去行山，就萬無一失喇！
      带埋手提电话去行山，就万无一失喇！
      daai3 maai4 sau2 tai4 din6 waa2 heoi3 haang4 saan1, zau6 maan6 mou4 jat1 sat1 laa3!
      Bring along the mobile phone to go hiking and we'll be perfectly safe.
Definitions (Wiktionary)
  1. phrase, idiomatic
    infallible; surefire; perfectly safe
Definitions (Kaifangcidian)
  1. （沒有對應漢語詞彙）
Definitions (HSK3.0)
  1. HSK3 七一九级词汇表 #4261
Examples (粵典–words.hk)
  1. Cantonese
    带埋手提电话去行山，就万无一失喇！
    帶埋手提電話去行山，就萬無一失喇！
    daai3 maai4 sau2 tai4 din6 waa2 heoi3 haang4 saan1, zau6 maan6 mou4 jat1 sat1 laa3!
    • Bring along the mobile phone to go hiking and we'll be perfectly safe.