prim

A privet.

Precise or proper to the point of affectation; excessively decorous.

Strait-laced; prudish.

Neat and trim.

To fix (the face or mouth) in a prim expression.

To make prim, as in dress or appearance.

To assume a prim expression.

Neat; formal; stiffly precise; affectedly nice; demure.

A neat, pretty girl.