In Time of Plague

1. "They get restless at last with my indecisiveness and so, first one, and then the other, move off into the moving concourse of people who are boisterous and bright..." (654).

2. My guess: Based on the context I would guess is describing the people as loud and crazy.

3. "Noisy and lively; unrestrained or unruly" (Dictionary.com)
4. I was correct the context in which the word was used in this case helped me to understand what the speaker was attempting to say. Now I can picture with certainty a large, loud crowd that might be hard to make your way through or one that most try to avoid.