The word "boisterous" most nearly means clamorous.
Something that is boisterous is loud, noisy, and full of energy. It can also be used to describe someone who is outgoing and enthusiastic.
The other options do not have the same meaning as boisterous.
- "Ramshackle" means in a state of disrepair or neglect.
- "Steadfast" means firm in purpose or belief.
- "Unflagging" means continuing without tiring or weakening.