EIGHTEEN Antonyms There are 2 antonyms of the word eighteen. (opposite meanings)Did you mean?Definition of EIGHTEENBest Opposite Words For EIGHTEENTop 20Top 10 Top 20 (Default)Top 50 Top 100 All All (Default)WordsPhrases All All (Default)Verb Noun Adjective Adverb Expand?WordSave?Synonyms..UsageTypenineteennoun • the cardinal number that is the sum of eighteen and oneadjective satellite • being one more than eighteenseventeennoun • the cardinal number that is the sum of sixteen and oneadjective satellite • being one more than sixteen Alternatives for NINETEEN Words (1)nineteenAbbreviations (2)19xixOpposite words for nineteen Alternatives for SEVENTEEN Words (1)seventeenAbbreviations (2)17xviiOpposite words for seventeen