Normally, we say “bra and underwear” right? Female underwear is normally considered to be bikini, thong, boyshorts, hipsters, but NOT bras.
But…with the exception of sports bras, females don’t generally show their bras to people they wouldn’t show their underwear to. Going running in the summer in a sports bra is no big deal to many people.
But..it’s also the layer of clothing directly up against the skin, just like underwear.
With that said…it’s interesting what society has basically done about underwear. I’m not saying we should walk around in it, but some bathing suits show much less than some underwear and some people have no issues in skimpy bathing suits.