doctor
"Doctor" is a word most people know as the person who treats sick patients — but it actually has a few interesting uses. It works as both a noun and a verb, and the verb sense might surprise you!
A doctor is also someone who has earned the highest university degree, called a doctorate (or PhD). You do not have to be a medical doctor to use this title — a professor who studied history or science for many years can also be called 'Doctor'.
academia / education · Modern, widely used
The letter was addressed to Dr. Johnson, head of the linguistics department.
When used as a verb, 'to doctor' something means to change it in a dishonest or sneaky way — usually to make it look different from what it really is. Think of someone editing a photo to hide the truth, or adding something to food or drink without telling anyone.
everyday language / journalism / law · Modern, widely used · figurative