The phrase "weakness of flesh" can be defined as a physical or emotional weakness that hinders one's ability to perform at their best. Synonyms for this phrase include frailty, infirmity, debility, feebleness, vulnerability, imperfection, and fault. These words describe the state of being weak or vulnerable either physically or mentally. Each synonym carries its own nuance and can be used in different contexts depending on the situation. For example, frailty suggests a delicate and easily breakable nature while imperfection implies a lack of flawlessness. By using these synonyms, one can convey a nuanced understanding of the weakness of flesh and its impact on individuals.