The hotel was cheap, but the lobby was shabby-looking.

shabby-looking 是由形容词 shabby（破旧的、破败的）和现在分词 looking（看起来）组成的复合形容词。shabby 本身表示"破旧的、邋遢的"，加上 looking 后强调"看起来破旧的样子"。整个词描述一种外表破旧不堪的状态。