noun, na-adjective, noun which may take the genitive case particle 'no'
bold and unrestrained; daring and unfettered
Describes a person, action, or style that is audaciously free-spirited, often with a positive or admiring tone. Can be used as a noun, na-adjective, or no-adjective.
His bold and unrestrained ideas gave birth to the new product.
The painter is known for his daring and unfettered brushwork.
大胆 means 'bold' or 'daring' and is more common; 大胆奔放 adds the nuance of being unrestrained or free-spirited.
奔放 means 'wild' or 'uninhibited' and is often used in compounds like 自由奔放; 大胆奔放 combines boldness with that lack of restraint.
A yojijukugo (four-character compound) combining 大胆 (bold, daring) and 奔放 (unrestrained, free). The exact origin is uncertain, but it follows a common pattern of pairing near-synonyms for emphasis.