Syphilis is a bacterial/viral STD, while Leucorrhoea is a viral/protozoan STD.

Explanation

**Step-by-Step Solution:**

1. **Identify the Diseases**: The question mentions two diseases: Syphilis and Leucorrhea. We need to determine the type of pathogen (bacterial, viral, or protozoan) that causes each disease.

2. **Understanding Syphilis**: Syphilis is a sexually transmitted disease (STD). It is important to note that it is specifically caused by a bacterium known as *Treponema pallidum*. Therefore, we classify Syphilis as a bacterial STD.

3. **Understanding Leucorrhea**: Leucorrhea is also classified as a sexually transmitted disease. It is primarily caused by the protozoan parasite *Trichomonas vaginalis*. Thus, we classify Leucorrhea as a protozoan STD.

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