advocate
An advocate (AD-və-kit) is someone who supports a cause, like an advocate for outdoor recess. Advocate (AD-və-kate) is also a verb meaning to speak in favor of, so you can advocate for that outdoor recess by urging your school to play outside!
As a noun, an advocate is a person who represents another person’s interests, like a lawyer does. In fact, the word comes from the courtroom – it’s from Latin advocare, to “add” a “voice.” To advocate is to add a voice of support to a cause or person. An advocate is anyone who adds that voice by representing another person in court, or by supporting or working toward a particular course of action.
lieu
To be in lieu of something is to replace it or substitute for it. A restaurant that's run out of clams might serve French onion soup in lieu of chowder.
The word lieu originally comes from the Latin locus, meaning "place," and its meaning has stayed true to its origins ever since. Though it does have a standalone definition, "the position or function formerly held by another," this noun is most commonly encountered in the phrase "in lieu of," which means, basically, "instead of."
obstruct
When you obstruct something, you block it. If you’re gobbling down your pizza, a chunk of crust you didn’t chew so well might obstruct your airway and you'll choke.
Obstruct also means to get in the way so that you hide something from view. That fast food tower being built next to your beach house will obstruct your lovely ocean vistas. And that scene gives you a vivid illustration of the Latin roots the word comes from: ob- "against," and struere, "build." You can also obstruct something or someone by putting up a roadblock, literal or figurative: when you park yourself by the exit door, you obstruct everybody's way out.
obfuscate
Some people are experts at obfuscatingthe truth by being evasive, unclear, or obscure in the telling of the facts. The people who are good at obfuscating would include defense lawyers and teenagers asked about their plans for Saturday night.
Although the verb obfuscate can be used in any case where something is darkened, less clear, or more obscure, it is most frequently used in reference to things like ideas, facts, issues, or the truth. The usual implied meaning is that this obfuscation is done deliberately. Politicians often obfuscate the truth about the issues to win support for their positions so they can win elections.
eradication
When people talk about the eradication of something, they are referring to its total destruction. Imagine a movie villain destroying a planet with a massive laser beam and you'll have the right idea.
If a gardener's goal is the eradication of every single weed in his back yard, he might start by uprooting dandelions. Fittingly, the root of eradication is the Latin word for "uproot," ērādīcāre. The eradication of anything, whether it's disease, poverty, war, or weeds, involves removing every last trace of it, right down to the roots.
systematic
Systematic describes something that is planned out and careful. In your systematic search for your mother's car keys, you start in one room, looking everywhere from bottom to top before moving to the next room.
Use the adjective systematic to describe things that are orderly and efficient. The Latin root of systematic is systema, an arrangement or system. Think about a multi-step process that you have found the fastest and best way to complete — you do it over and over. You might be systematic about packing for a long trip or the way you travel up and down the aisles at a grocery store, probably with a list in your hand.