Phoebe Snow is by her own definition a hopeless "zhlub," a Yiddish word meaning clumsy, gauche and graceless. She grew up in adolescent misery in Teaneck, N.J., cursed by a weight problem and a God-given frizz in the golden age of pageboys. Her secret fantasies were of "salad bowls filled with spaghetti and tomato sauce that I could eat with my hands." Even now, at 25, Phoebe and her husband, Phil Kearns, live on the wrong side of the Hudson River in a one-bedroom flat in Fort Lee. To the record industry it is worse than Siberia; it is New Jersey.

But Phoebe Snow can go home whenever she wants. All is forgiven in the thrall of the music that is making her the newest of pop's matriarchs. Her two hit albums, mostly written by and about herself, blend a rich and sinuous voice with complex jazz and blues melodies that invite comparisons with Marilyn Home and Billie Holiday. No less an authority than Paul Simon calls Phoebe the best singer anywhere.

Her current boom began in December when she gave birth to her Second Childhood album and her first baby, a 5-lb., 4-oz. daughter named Valerie Rose. Last summer, Phoebe and Phil, a folk singer, were unmarried and had in fact briefly separated when, Phoebe recalls, "I went to an internist because I thought I was dying or had an ulcer or something. Why else would I be throwing up every morning? He said, 'Either I'm crazy or you're five months pregnant.' I said, 'You're crazy.' He said, 'Nope, guess again.' When I went to see Phil, I said, 'I'm going to have a baby.' He screamed, 'I love you. Marry me.' "

About that time, Phoebe was grinding through a 46-city tour of one-night stands. "Everything was totally anti-baby," she says. "I don't know how this kid survived." But, she adds, "The baby was good for creativity. I'd lean my guitar against my stomach and that part of my stomach would bulge back and go 'whoooaaaa.' She was listening."

Phoebe picked up her interest in music at home, where her mother was a former Martha Graham dancer and her father was a Benny Goodman buff who worked for an exterminating company. (Her actual surname is Laub; "Phoebe Snow" was borrowed from an Erie Lackawanna train.) Phoebe's parents gave her the obligatory piano and guitar lessons, though her real inspiration came from jazz and blues records. School, according to Phoebe, was an agonizing exercise in social maladjustment. "All I wanted was to wear knee socks, plaid skirts and bangs and be inconspicuous," she says, with typically lacerating self-analysis. "But I stuck out like a sore thumb. I used to walk around with my notebook in my face."

She dropped out of Shimer College in northern Illinois and fled to Greenwich Village and the life of a quasi hippie, smoking dope and crashing on uppers and downers. An early boyfriend encouraged Phoebe to perform the stream-of-consciousness lyrics she'd been scrawling in her notebooks for years. In 1970 he died of an overdose of antidepression drugs, a tragedy that Phoebe once said was "the worst thing that ever happened to me." One of her most affecting songs, Harpo's Blues, is about his death.

Phoebe's break came after a record producer spotted her at amateur night at New York's Bitter End nightclub. Her first single, Poetry Man, was a hit in 1975, and its brooding, bluesy LP, Phoebe Snow, coined gold with a minimum of hype.

Her baby, Phoebe believes, is providing the serenity that's finally anchoring her life. She's given up all drugs, even aspirin, and two other minor vices, Twinkies and cheesecake. "I got off by being crazy in my younger days," she admits. "Because I was irresponsible I didn't think I could manage myself and another person, too. Of course," she jokes, "it's true that I'm still out of my mind. You have to be nuts to be in this business. But they're not going to get my kid."

Phoebe and Phil, who now helps manage her career, are house-hunting in northern New Jersey and next month will take off on a nationwide concert tour. "I never thought I'd sing for a living," Phoebe says wonderingly. "Of all my childhood fantasies, this was the most ludicrous." Well, almost. Phoebe's other musical dream is to be reincarnated as a saxophone.