Kanye West's wife -- famous for walking around in everything but her birthday suit -- seems to have wandered over into stark naked territory after pushing the envelope for months ... or at the very least, she was doing that upstairs ... 'cause her bare breasts were on display.

Indeed ... Bianca was leaving a tanning salon in L.A. Monday -- and on her way out to her car, she stepped out in this little number, which was devoid of any sort of bra under her top.

The reason that's relevant ... her shirt was completely see-through and probably doesn't qualify as an actual garment of clothing -- like we said, it's like she's wearing nothing at all on her torso except what her mama gave her ... and in this case, that's huge ol' boobs!

Bianca's bottom half wasn't very covered up either, BTW ... but the focus here is definitely on what's going on closer to the attic -- and it's certainly a sight for sore eyes to start the week.

We'll say this ... she topped herself after her ensemble this weekend, which was just as wild.

In terms of her headwear ... she was rocking a very patriotic camo-colored hat with an American flag emblazoned across the front -- and that's interesting considering who's speaking at the Republican National Convention ... one Amber Rose, KW's ex-GF.

She herself has recently come out as very pro-MAGA -- and she's endorsed Donald Trump ... getting tapped as one of the key speakers for the GOP event. It's an interesting Ye tie.

We know Kanye is a diehard conservative himself ... and with Bianca's attire choice for this outing, ya gotta wonder if those views are rubbing off on her as well of late.