This word is acceptable for play in the US & UK dictionaries that are being used in the following games:

• Lexulous
• Wordscraper
• Wordosaur

ad. In a boisterous or unruly manner

"Those five chapters were the start of her children's debut Fly By Night, a rumbustiously imagined rollick through the adventures of the black-eyed orphan Mosca Mye and her pugilistic goose Saracen."

rumbustiousness