7hūng sam louh gūn 空心老柿/借/官 — a person of little substance, a person with pretensions but with nothing substantial to back them up.
8hūng tàuh ji pui 空頭支票 — a cheque which cannot be cashed, a cheque that bounces; a promise that is not likely to be fulfilled, an empty promise (ty 9.10.2000, A6).