"a deep cleavage" is correct and usable in written English.
You can use it to refer to a physical cleft between two parts of the body, such as between a woman's breasts. For example, "Her low-cut top revealed a deep cleavage".
Over in the Valley, a deep cleavage of greenery and ancient trees, Derrick Carter's perfectly judged 2am house is elegantly lit by Tracey Emin-inspired neons.
The centerpiece of Schlick's early epistemology is a deep cleavage between intuitive acquaintance and conceptual knowledge.
As might be expected, the Board's output is marked today by a deep cleavage between Republican and Democratic members over literally dozens of issues.
In August 2006, Kaniuga revealed three additional alternate designs on ConceptArt.org's internet forum; one being the classic look; another being a white button-up shirt with red pants, high heels, and short hair; and the third keeping the high heels and pants, but adding shades, returning her hair to full length and swapping the shirt for a jacket with deep cleavage.
She is a bottle blonde with deep cleavage and bears more than a passing resemblance to Mae West.
"Deep cleavage is a decided plus," he said.
Where just months earlier Cosmo's covers had featured photos of demure, high-collared girl-next-door types like Mary Tyler Moore, Ms. Brown's first issue, July 1965, showed a voluptuous blond model whose deep cleavage was barely contained by her plunging neckline.
The couple's wedding, at the Metropolitan Building in Long Island City, Queens, was scheduled for 7 p.m. on June 5 At 6 38, as Ms. Cohn -- in a Vera Wang wedding gown that had deep cleavage, front and back -- was primping for the ceremony, Mr. Siegel and some of his friends were sitting in front of a tiny television, watching Smarty Jones run in the Belmont Stakes.
A deep cultural cleavage divides the two groups, with the blue-collar workers who have come here from all over the country profoundly resentful of the young "Clean for Dean" volunteers.
Overheard of the year At Cannes, as men's heads turned when a beautiful French star sashayed into the opening night party, displaying deep cleavage, another (older, very established) French actress told her entourage: "Yes, but you know they're not real – nobody's are these days".
The film, based on the life of a real person (who has been turning up on talk and awards shows herself), deteriorates into a do-gooder soap opera, but Ms. Roberts, memorable in micro-mini hemlines, deep cleavage and cheap jewelry, keeps things lively -- Saturday at 8 p.m. and Saturday/Early Sunday at 3 20 a.m. on Starz.
