The term 'sinister stare' can be broken down into two crossword solutions: 'LEER' (4 letters) and 'evileye' (7 letters). A LEER is a type of facial expression that conveys a feeling of disdain, mockery, or scorn. It is usually done with one eye partially closed and the mouth slightly open. An evileye is a type of stare that is meant to intimidate or frighten someone. It is often associated with supernatural forces and is believed to bring bad luck or misfortune. Both terms are used to describe a menacing or threatening look.