The onus is a term that refers to a responsibility or a burden that one carries. There are several other synonyms that can be used to convey the same meaning. One of the most common synonyms for the onus is the burden, which can be used to represent any obligation that one has to fulfill. Another synonym is the responsibility, which refers to the duty or task that one needs to accomplish. Others include the weight, obligation, or liability, which conveys a sense of responsibility or duty that one is required to fulfill. These synonyms can help to add variety to our language and make communication more interesting.