adjective
emphatic
em-FAT-ik/ɪmˈfætɪk/
Expressed or done with force and certainty.
His outward palm and turned head make the refusal emphatic.

Etymology
The underlying image is of showing something within an expression. Through the rhetorical sense of suggesting extra meaning and stressing it in delivery, emphatic came to describe forceful, strongly expressive words.
In context
using an emphatic gesture this time as part of a joke now what these gestures do is they accentuate what he's saying
More examples
- An emphatic gesture ended the debate.
- He was emphatic about the need for accuracy.
- The team celebrated an emphatic victory.
Forms
emphatic · more emphatic · most emphatic
emphasis noun — special force or importance
Similar words
- forceful
- Forceful means strong in expression; emphatic particularly stresses certainty or insistence.
- definite
- Definite means clear and settled; emphatic adds expressive force.