1. Literal Meaning: Some suggest the phrase may come from the literal meaning of "bib" and "tucker." A bib is a piece of cloth worn to protect one's clothing while eating, while a tucker is a piece of fabric used to cover the neckline or bosom. The phrase could imply wearing one's best bib and tucker, suggesting one's finest attire.
2. Working Class Term: Another theory suggests the phrase originated in the working class. When workers wanted to express their best dressed state, they would refer to their best "bib and tucker," which symbolized their best clothes, even if still modest by upper-class standards.
3. Cockney Rhyming Slang: Some also suggest a link to Cockney rhyming slang, where "bib" could be rhyming slang for "tipple" (drink), and "tucker" could be rhymed with "ducker" (duck), implying getting dressed up for a tipple and duck, or simply having a good time while dressed up.
4. Naval Tradition: Another possibility is that the expression originated in the British navy. Sailors might refer to their best clothing as their "best bib and tucker" when appearing for important occasions or shore leave.
Despite these various theories, it's challenging to pinpoint the exact origin with certainty. The phrase has evolved and become an established idiom in English, symbolizing one's finest attire. It's particularly used to describe someone's Sunday best or formal clothing, often implying a sense of putting on one's best appearance for a special event or occasion.