To be very knowledgeable about, skillful in, or competent at something. John is well versed in lying, so he's always able to talk his way out of trouble. You should talk to my friend Ana, she's very well versed in the ins and outs of income tax.

To train, familiarize, or educate someone or oneself in or about some field or activity. Often used in the passive construction "be (well) versed in (something)." Our program is intended to verse older customers in the basics of the computer's operating system. As a project manager of over 15 years, I'm well versed in overseeing large teams and meeting deadlines. I versed myself in three different languages while I was in college.