Question

what would be the sign of accleration if body is thrown vertically

Answer 1

Question is incomplete (in my sense)

Still yet if the body is thrown vertically upward then the sign of acceleration shall be -ve . This is because in that case the force of earth or you can say gravitational force acts on body to attract it towards itself. Hence, for it must reduce its acceleration.

And if body is thrown vertically downward then the acceleration shall be +ve.