"Prehend-" means "to seize, grasp, or understand". It's related to words like:
* Comprehend: To understand fully.
* Apprehend: To arrest, seize, or understand.
* Reprehensible: Deserving blame or censure.
For "nervous" and "fearful", you'd look to other Latin roots like:
* "tremere": to tremble (nervous)
* "timere": to fear (fearful)
Let me know if you'd like to explore the meanings of these roots further!