life jacket
Word family adjectivelifefullifelesslifelikelifesomelifeholdlifelonglife-savinglife-sizeadverblifelesslynounlifelessnesslifelikenessliferlife assurancelifebeltlifebloodlifeboatlifeboatmanlifebuoylife coachlife cyclelifeguardlife historylife jacketlifelinelifemanshiplife peerlife raftlife sentencelifespanlife storylifestylelifetimelife
Water
ldoce_201_aˈlife ˌjacket noun [countableC] British EnglishBrE 
TTWa piece of clothing that can be filled with air and worn around your upper body to stop you from sinking in the water 救生衣 SYN American English life vestExamples from the Corpus
life jacket• School was very important, a life jacket in chaos.• Despite my life jacket, I was pinned under water by the down-surging river hydraulic.