A face that is expressionless, especially not laughing.
straight-face test
A tongue-in-cheek test of the merits of an argument which asks whether …
straight from the horse's mouth
firsthand; direct; from the source.
straight and narrow
A path of honesty; a procedure according to rules and plans.
straight out of the chute
immediately, from the very outset.
straight man
A member (of any gender) of a team of comic performers who plays a sup …
straight away
Very soon; quickly; immediately.