A large increase in activity or in the level of something. (Cambridge Dictionary)
Buildup, increase. (Merriam – Webster)
To increase or cause to increase. (Collins Dictionary)
To increase the effort involved in a process. (Collins Dictionary)
An increase in quantity, pace, output, intensity, etc.; a boost. (Oxford Dictionaries)
Civil service told to ramp up no-deal Brexit plans with 24/7 crisis centre.
15 Simple Ways to Ramp Up Your Online Marketing.