The word "was source of strength" can have several antonyms, depending on the context in which it is used. In the case of a person or organization being a source of strength, some antonyms could include weakness, liability, or hindrance. If the source of strength is referring to a positive or uplifting situation or experience, some antonyms could be negativity, discouragement or setback. Alternatively, "was source of strength" may refer to a specific attribute or quality, such as resilience or perseverance, in which case the antonyms could include frailty, frailness, or vulnerability. Ultimately, the antonyms for the word "was source of strength" will depend on the specific usage of the term.