This phrase implies repetitive emphasis over time, not just once. During the meeting, she continued to hammer home the importance of customer satisfaction.
Pro Tip 2/3
Intensity
The phrase suggests a strong, almost forceful, determination to make a point clear. He hammered home the need for safety protocols at the construction site.
Pro Tip 3/3
Convincing
Used when trying to persuade others or convince them of your position. The lawyer hammered home each evidence to prove his client's innocence.