The phrase "put across" is often used to convey an idea or message clearly and effectively. However, there are plenty of synonyms that can be used to achieve the same effect. To convey an idea or message, one could use synonyms such as "communicate," "convey," "share," "express," or "articulate." Other options could include "present," "impart," "propagate," "promulgate," "transmit," or "circulate." Depending on the context, other alternatives like "get through," "drive home," or "make understood" could also be used. Whatever synonym is used, the aim is to convey the idea or message in a way that is clear, concise, and easily understandable.