Adjective
1. 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""ugly black clouds""the situation became ugly"2. 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"-Thomas Hardy3. on or starting from the wearer's left;
"bar sinister"