General:
* Acting ability
* Thespian skills
* Performance abilities
* Stagecraft
* Dramatic talent
* Acting prowess
More specific:
* Delivery (for voice and speech)
* Stage presence (for physicality and charisma)
* Emotional range (for conveying different emotions)
* Method acting (for a specific acting technique)
* Naturalism (for a realistic acting style)
* Improv skills (for improvisational ability)
More informal:
* Acting chops
* Acting chops
* Talent
* Charisma
* Stage presence
The best synonym will depend on the context and the specific aspect of acting you want to emphasize.