The phrase "filling bill" means to meet a specific need or requirement, but there are antonyms to this phrase that describe the opposite situation. Instead of "filling bill," one might use the antonyms "falling short" or "missing the mark" to indicate that an item or action does not meet the necessary criteria. Alternatively, "excess" or "overkill" can be used as antonyms to describe a situation where too much of something is provided, going beyond what is necessary or desired. By using antonyms to "filling bill," speakers can highlight when something is not quite right or does not meet their expectations.