The phrase "deliberate on" refers to the act of carefully thinking about something before making a decision or taking action. However, there are many other synonyms that can be used in place of "deliberate on" to convey a similar meaning. Some options include "consider," "contemplate," "ponder," "reflect on," "mull over," and "weigh." Each of these words suggests taking time to think through a situation carefully before responding. Using different synonyms can help to vary your language and make your writing or communication more interesting and engaging, while still conveying the same message.