From Longman Dictionary of Contemporary Englishbe a pillbe a pillAmerican English informalANNOY if someone, especially a child, is a pill, they are annoying Luke can be a real pill sometimes. → pill
Examples from the Corpus
be a pill• What investors in drug firms really need is a pill to calm their nerves.• These may either be addictive themselves or may reinforce the view that there is a pill for every ill.• There are pills, one for every morning which you take each morning on the way to work. 