Sinistrous, meaning left-handed or left-leaning, has resulted in many synonyms over the years. Some of the similar words that are commonly used to describe this trait include sinister, leftward, unpropitious, unlucky, unfavorable, and disastrous. You could also use words like inauspicious, ill-omened, or ill-fated to describe something that is considered unlucky or brings bad luck. Furthermore, unfavorable and unpropitious suggest a sense of negativity or disapproval, while sinister is more ominous and foreboding. These synonyms can work well in descriptive writing, storytelling, or even in daily conversations when you're trying to find different ways to describe something or someone that is sinistrous.