1. To show or provide evidence of having a particular trait, attribute, or characteristic. The new method proved to be useful in detecting radiation. She's proven a reliable ally in my time at this company.

2. To show or provide evidence that someone, something, or oneself has a particular trait, attribute, or characteristic. In this usage, a noun or pronoun is used directly after "prove." The new computer's incredibly reliable CPU and sleek design prove it to be a worthy investment for any student or professional. The week I had to spend in New York proved Janet to be more than capable of running the office on her own. This new evidence proves him a liar.