Read the excerpt below and answer the question. I broke and reached him a flagon of De Grave. He emptied it at a breath. His eyes flashed with a fierce light. He laughed and threw the bottle upwards with a gesticulation I did not understand.
I looked at him in surprise. He repeated the movement --a grotesque one.

What is the meaning of the word gesticulation in the passage above?

utterance
signal
oath
phrase