ABB pattern, adjective + reduplicated suffix 巴巴 to vivify it. Same structure as 干巴巴 (dry-as-dust), 紧巴巴 (tight-and-strained), 眼巴巴 (eyes-pleading). The 巴巴 adds a visible, almost cartoonish quality.
usage
Often goes with 地 + verb (to describe how someone does something) or 的样子 (describing an appearance). Common in writing about pets, children, and people putting on a sad face.
