Definitions
1.nounA particularly difficult question or puzzle.
2.nounSomeone who asks a question or sets a problem."Even as a child, she was a habitual poser of difficult questions."
3.nounSomeone who, or something which, poses; a person who sets their body in a fixed position, such as for photography or painting.
4.nounA poseur; someone who affects some behaviour, style, attitude or other condition, often to impress or influence others.