Billie Eilish Blasts Haters Labeling Her 'Sellout' for Dressing More Feminine

Billie Eilish has mostly ditched the tomboy style that she got famous with, and is dressing more like a grown-ass, sexy woman ... something her haters can't deal with, it seems.

The pop star addressed this ongoing annoyance head-on this weekend with some telling Instagram posts that dove into what she makes of a select few saying she's a "sellout" for switching up her style and looking more lady-like as she gets older. Her message ... get bent.

Actually, she had a bit more to say about it ... and she got pretty deep in her dissection.

In since-deleted IG Stories -- featuring close-up shots of her mug -- Billie wrote, "i spent the first 5 years of my career getting absolutely obliterated by you fools for being boy ish and dressing how i did & constantly being told i'd be hotter if i acted like a woman."

She goes on, "and now when i feel comfortable enough to wear anything remotely feminine or fitting, i CHANGED and am a sellout ... and 'what happened to her' oMg iT's nOt thE sAmE biLlie she's just like the rest blah blah ..." BE adds, "you guys are true idiots LOL."

Billie hits her point home ... "i can be BOTH you f***ing bozos. LET WOMEN EXIST!" She also threw up extra IG posts for good measure, noting femininity in and of itself doesn't equal weakness ... and that women just *might* want to express themselves differently at different times for a variety of reasons. In other words, she ain't a one-trick fashion pony.

It's unclear what exactly may have sparked Billie's latest thoughts on this -- she's addressed the same thing in the past many times over -- but it could be a recent IG where she's showing off some skin. She's been doing that quite a bit lately ... landing major fashion magazine covers and rocking a variety of outfits she hasn't traditionally been known to wear.

She's gotten a lot of praise for embracing new looks ... which was jarring at first, for some, considering how strongly tied her brand/artist identity was with her oversized, wacky clothes.

Billie's also aged and matured -- both physically and artistically -- right before our eyes over the years ... going from a teen goth pop queen to a nuanced, Grammy-winning musician with a ton of accolades/collaborations. So, even in that sense -- she's changed quite a bit.