Use the adjective zoftig to describe an attractively curvy or voluptuous woman.
When you talk about your zoftig friend, you are describing her as well-proportioned, healthy, and shapely. Zoftig women aren't skinny — they are pleasantly curvaceous. It's more common to spell the word zaftig instead of zoftig, but both spellings are correct and come from the Yiddish zaftik, or "juicy." Its root, in turn, is the Middle German saft, "juice."