Slang: White Bread

"White bread" means common or boring and is slightly derogatory.

Somebody say it means a white sexy girl, is this relevent?

Relevant? Nope.

Was there any context along with the phrase, Lilian? That would go a long way to determining the meaning.

I think "conventional" may be correct. I'll check when I meet my colleague again. Thank you!!!

White bread is an idiom used to decribe something bland or non descript, and it can also describe a boring white person or thing.

"That dress is so white bread" could mean it is boring.

"That car is so white bread" would mean it looks typical of what a boring white person would drive or typical of what everyone else has.

I first heard this phrase on the Simpsons in the episode where Homer writes the song everyone hates Ned Flanders, and Apu uses the phrase 'He's so white bread.' At first I just thought it was an American version of rhyming slang, but then it dawned on me that Americans don't do rhyming slang. So I googled it to come up with this link. It is an Americanism, and wouldn't catch on over here, basically because it's too close to rhyming slang. Rhyming slang in this case is always used as a threat. That bloke's brown bread/dead.