Betty Thomas is a big woman. A BIIIIIIIGGG woman.

She plays the wisecracking cop Lucy Bates on the hit television series "Hill Street Blues," and looks like Harpo Marx on stilts and sounds like Sylvester Stallone. She smokes cigars, rides a motorcycle and knows kung fu. When she wore a tie under her sweater to the airport the other day, the clerk never looked up. He just said, "Thank you, sir."

Betty Thomas is one tough broad.

"Merv Griffin always says I intimidate the hell out of him."

She sticks an unfiltered Camel into her mouth, lights it and crosses her legs, which are the length of most people's floorlamps. That's because she's 6-foot-1 and wears black leather shoes with four-inch spike heels. Size 10. No wimpy flats for this highball, known as "Stretch" to her childhood acquaintances.

"It's better than being called 'Fatty,' " she deadpans.

Her gray wool sweater dress is cinched at the waist with a silver belt buckle the size of a small foreign car. On her wrist is a three-inch-wide silver bracelet. Her large brown eyes peek out from under a mop of yellow, naturally defiant hair. Big gestures. Big laugh. The whole effect is larger than life.

Since she plays the part of Lucy Bates with equal gusto, Thomas was in town last week to receive an award from the National Commission on Working Women. She was cited for her "excellent portrayal of a working woman in a nontraditional role."

"I went to a training class for women police officers one day. There were all these women, totally different. I thought, 'How can Lucy Bates be all these people?' That was a problem for me for a while. I gotta represent all the female cops in the world. I really thought that.

"One time I had a police officer come up to me. She hated it when I smoked a cigar. She said, 'You gotta be careful. Don't forget you're a woman.' I said, 'I know, I know.' " She stabs the air with another Camel. "But why can't I be a woman and smoke a cigar?"

She says "Hill Street Blues" is a great place to work, but the Emmy Award-winning show's reputation for gritty realism doesn't necessarily make it true to life. For one thing, although men and women police officers who work as partners on the same beat in real life receive the same salary, she and her "Hill Street Blues" co-star Ed Marinaro do not. "I won't tell you what I make and I won't say what Ed makes, but the gap is $2,500 per week."

Yes, she says, "It ------ me off."

She stubs the cigarette out. And another thing, she says, "I think there's fantasy on 'Hill Street.' A lot of fantasy. I don't think it's really reality at all. The real reality, believe me, stinks. You can smell it. Right here." She holds her nose.

A report issued by the National Commission on Working Women this week showed that women on television bear almost no resemblance to their counterparts in real life -- which is no surprise to Betty Thomas. "There are no real women like Morgan Fairchild. This is a creation."

Still, the lanky Thomas longs to break out of her macho policewoman image. "I'd love to play a rich, hotshot bitch," she says.

After 10 years of show business, 35-year-old Thomas has made it. Not on her looks, on sheer talent. She's broken the beauty barrier, bringing to the screen her own brand of bawdy humor and candor. "You don't have to be a knockout to be on television," she says. "But you have to be acceptable. It can be your humor."

Betty Thomas was born Betty Thomas Nienhauser and grew up in Willoughby, Ohio, a shy, middle-class, suburban child. Her mother didn't think she'd ever stop growing. "At 13, I got over six feet. I thought, Gaaawdd, this is terrible, I'm gonna kill myself. But the next year I got this cute boyfriend, who was taller than me, and since then it's never made any difference."

In 1969, she graduated from Ohio University with a degree in fine arts. She taught school in Chicago before breaking into show business by waiting tables at Chicago's famed comedy playhouse, Second City, which also spawned Dan Aykroyd, John Belushi and Bill Murray. She went to Los Angeles and taught improvisational comedy before landing a bit part in the pilot for "Hill Street Blues." As the story goes, then-NBC head Fred Silverman took one look at Thomas' performance and signed her as a regular.

At first, she admits, she had a sizable crush on the show's star, Daniel Travanti. Then, when former Cornell football star Ed Marinaro was hired to be her partner, she almost died. "I could kill the people who hired him. I felt uncomfortable. I mean, he's kinda neat you know, I mean he comes on all the time, every minute of his life. Like the cute guys you knew all your life? The ones you always wanted but couldn't have? Now, I know him so well, he's like my brother."

Thomas has just broken up with her live-in boyfriend, comic Robin Eurich, and dates a few men. She has a fan club. "Henry Winkler loves me. Every time he sees me he comes up and gushes."

She was saddened by the loss of her friend, John Belushi. "I was totally shocked. Stunned. Wiped out. I had just spent Christmas with John and a lot of people." Self-destructiveness, she says, comes with the territory. "You see it all over Hollywood. I could name 10 people I've seen do crazier things than I ever saw John do."

Eventually, she'd like to do movies. Maybe direct. She says there are many possibilities and "Hill Street Blues" is just the beginning. "This is just a touch," she says, dragging on a Camel and crossing her long legs. "But what a nice touch.