ˈbeɪl.fəl blæk fɚˈbɪdɪŋ fəˈbɪdɪŋ ˈmɛnɪsɪŋ mɪˈneɪʃəs ˈɒmɪnəs ˈɑmɪnəs ˈsɪnɪstə ˈsɪnɪstɚ ˈθɹɛt.n̩.ɪŋ threatening or foreshadowing evil or tragic developments a baleful look forbidding thunderclouds his tone became menacing ominous rumblings of discontent sinister storm clouds a sinister smile his threatening behavior on or starting from the wearer's left bar sinister stemming from evil characteristics or forces; wicked or dishonorable black deeds a black lie his black heart has concocted yet another black deed Darth Vader of the dark side a dark purpose dark undercurrents of ethnic hostility the scheme of some sinister intelligence bent on punishing him