When it comes to finding synonyms for the phrase "weak soul", there are a variety of options to choose from. Some possible choices might include words like "frail," "timid," "spineless," "fainthearted," "insecure," "unassertive," "needy," or "uncertain." Each of these terms conveys a sense of vulnerability, hesitation, or lack of conviction. It's important to note, however, that while these words can be useful for describing someone who might be struggling with confidence or perseverance, they don't necessarily capture the full complexity of someone's character or spirit. As such, it's important to approach labels and descriptions with empathy and understanding, recognizing that everyone has strengths and weaknesses, and that a person's soul cannot be reduced to any one word or phrase.