WHEN PAINTER Alice Neel finished her 1964 portrait of Julie Hall, a college-age friend of one of the artist's children, Neel offered it to the young woman's mother, who declined it -- because the sitter was not smiling. Based on some of the other images in "Alice Neel's Women," a long-overdue look at the work of the great portrait painter at the National Museum of Women in the Arts, a poker face was the least of the mother's worries.

Neel, you see, just wasn't very good at flattery.

Sure, there are some pretty pictures in the show. But Neel, who called herself a "collector of souls," was far better at capturing something ineffable, true -- yet often hidden -- about her subjects than she was at making them feel good about themselves. With sitters posed in frank, starkly frontal postures, emotionally exposed and sometimes literally naked, Neel's portraiture is as raw and unidealized as the frequently unfinished canvases and slightly off-kilter compositions that are the artist's hallmark. She wasn't done when she'd filled in every inch of the canvas with paint, or when she'd fixed your likeness, but when she'd gotten you.

Every bit of you. And if that you happened to be naked, except for a pair of shoes, and spread-eagle on a couch -- as was the case with 19-year-old Standard Oil heiress Pat Ladew, who was so discomfited by her own 1949 portrait that she eventually traded it back to the artist for a still life -- oh, well.

And that's if Neel liked you. Woe unto you if you chanced to wind up on Neel's bad side. That's what happened, apparently, to Audrey McMahon, the New York regional director of the Works Progress Administration from 1935 to 1943 (and Neel's supervisor during the artist's Depression-era stint as a WPA artist-employee). The 1940 portrait of McMahon, described on the wall label, with dramatic flourish, as Neel's "nemesis," brings such hideous distortion of its subject to bear -- a stick-like forearm and clawed hand; dark, sunken eyes; and a cruel, pinched mouth -- that it makes Cruella De Vil look like Mother Teresa of Calcutta.

Or maybe she just looked like that.

The McMahon portrait actually appears twice in "Alice Neel's Women," the second time in the background of "Nancy and the Rubber Plant," a 1975 picture of Neel's daughter-in-law and studio assistant that is, according to curator Carolyn Carr, one of Neel's most "accomplished" paintings. Although it certainly is, at least formally, accomplished, it is no more telling -- or compelling -- a portrait than many others. Take, for example, "Last Sickness" (1952-53), a portrait of Neel's elderly mother not long before her death in 1954. Or "Religious Girl" (1958), whose anonymous subject seems caught in a moment of ecstatic spirituality. Feel what Carr calls the "edgy" psychosexual tension and "film noir character" of "Jackie Curtis and Ritta Redd" (1970), a study of a gay male couple that is just one of several of the show's double portraits, a favorite format of Neel's.

Yes, despite the title, "Alice Neel's Women" is not all women. Transvestite Curtis (star of Andy Warhol's "Flesh") and his boyfriend are just a couple of the subjects here who are male -- sometimes quite unmistakably so, as in the case of the almost freakishly well-endowed Egil Hoye, seen in a double portrait with his equally naked wife, Nadya Olyanova.

It is, however, the female sitters with whom this exhibition -- if not Neel -- is most fascinated. It is also they who give "Women" its political bent. It can be seen in Neel's frequent return to the theme of motherhood and pregnancy (a condition about which the artist was, by her own admission, somewhat ambivalent). And it can be seen in the ongoing artist-subject relationship between Neel and such repeated sitters as Olyanova. The Ukrainian-born handwriting expert's strong sexuality was seen as both a source of power and liberation to Neel, but also, as in "Degenerate Madonna" (1930), which depicts Olyanova with the ghosts of aborted babies, something vaguely sad. Throughout the show, there is a strong sense of female energy.

Of course, it's never only about sex and reproduction. Neel's portraits include women of great professional accomplishment, with an emphasis on the writers, curators, artists, art historians, art dealers and activists (both leftist and feminist) with whom Neel hung out. "Marxist Girl (Irene Peslikis)," Neel's 1972 portrait of the radical feminist artist and activist, is a good example of how the artist was able to telescope the personal and the political into a single gesture. Although Neel never told her subjects how to pose, other than perhaps to turn this way or that, the sitter's raised right arm, which reveals a defiantly unshaved armpit, tells us as much about Peslikis as it does about Neel.

It is, however, Neel's famous 1980 self-portrait, depicting the white-haired artist unashamedly naked at age 80, and with a paintbrush, naturally, that tells us the most about this remarkable artist. Not just about her ability to penetrate beneath the facade, but about her perverse affection for our flaws. In the words of New York Post critic Charlotte Willard (herself the subject of a 1967 portrait by Neel), "Even fully clothed, her sitters appear naked before us in their vulnerability, their bewilderment, their aggressions, their self-concern, their resignation. . . . Alice Neel puts them all down sharply -- the intelligent glance, the talon hands, the hostile stare, the defensive gesture, the suspicious eyes and the wasted body, the brave mouth, the debonair gesture. The fact that she records their presence is proof of her compassion."

ALICE NEEL'S WOMEN -- Through Jan. 15 at the National Museum of Women in the Arts, 1250 New York Ave. NW (Metro: Metro Center). 202-783-5000. www.nmwa.org. Open Monday-Saturday 10 to 5; Sundays noon to 5. $8; students and seniors $6; members and visitors 18 and younger free; free admission on the first Sunday and Wednesday of the month.

Alice Neel's 1940 portrait "Bessie Boris" at the National Museum of Women in the Arts. Alice Neel often painted fellow artists, including Faith Ringgold. "Marxist Girl (Irene Peslikis)" captures Peslikis's personality.