1. a sudden increase in something
a burst of energy/activity/anger/rage
There are a number of ways you can use this expression and some popular words that go with it. 'A burst of energy' is a sudden increase in energy or motivation, suggesting a short period of productivity: "I hope this coffee gives me the burst of energy I need to finish this essay." You can have 'a burst of activity' (although you won't hear this as much), or even 'a burst of anger' or 'rage', suggesting that these things only last a short time, and are usually unexpected. This is a phrase you will hear in professional and social contexts. Similar expressions include 'a surge in adrenaline', or 'a flurry of activity'.