just in case /ˌdʒʌst ɪn ˈkeɪs/adverb 1conjunction 2 adverb1 •To provide for a possible event as a precaution.I'll take an umbrella, just in case. conjunction2 •To provide for the possible event that.I'll take an umbrella, just in case it rains. •Synonym of if and only if.The negation of a disjunction is true just in case both disjuncts are false.
