一只倒霉的汤姆猫在英语中可以表达为 "a unlucky Tom cat"。这里的 "Tom cat" 指的是汤姆这只猫，而 "unlucky" 则表示这只猫运气不好，经常遇到倒霉的事情。如果想要创造一个更具体的描述，可以结合具体情境，例如：
- "The unlucky Tom cat always seems to be in the wrong place at the wrong time."
- "Poor Tom cat, he's had one disaster after another this week."
- "It's like bad luck follows the unlucky Tom cat wherever he goes."
