Hot answers tagged words
A pill is “a disagreeable or tiresome person,” often because he is a square (overly conventional) or a Debbie Downer (overly negative). Playing the pill means that he chose the role of a pill, rather than somebody witty and charismatic – like former president John F. Kennedy. It's not idiomatic, but merely colorful language.
Only top voted, non community-wiki answers of a minimum length are eligible