A word used to describe a female of a certain degree of attractivity. A female described as "couchworthy" has generally sizeable breasts and an appealing posterior. The term itself literally means that the female is attractive enough that the speak considers her worthy of being bent over against a couch for sexual activity.
"Dude, did you see that chick? She's so totally couchworthy!"
"Man, Susan's got such an ass. Couchworthy indeed."