When it comes to alerting someone about a potential danger, it is essential to use language that is clear and concise. The phrase "give due warning" is often used in this context, but there are several synonyms that can convey the same message effectively. Some of the alternative phrases that can be used to replace "give due warning" include "notify in advance," "forewarn," "caution," "preempt," "advise to be careful," and "issue a heads-up." Ultimately, the choice of words will depend on the situation and the urgency of the warning required. Irrespective of the verbiage used, it is vital to ensure that the message is conveyed accurately and in time to prevent any mishap.