ROOT / ROUT / ROUTE

You can root for your team (cheer them on) and hope that they utterly smash their opponents (create a rout), then come back in triumph on Route 27 (a road).

REQUEST / ASK

If you want something you can request it or you can ask for it. Many people like "request" because it sounds more formal, more elegant; but to other people it just sounds pretentious. There are many instances in which plain old "ask" works better: "I'm asking my Students to go camping with me." "She asked him to walk the dog."
Except on wedding invitations(Here requesting means compeling), try to avoid "request" where "ask" will do.

Don't request them you ask them to attend...

PSYCHOLOGIST/PSYCHIATRIST/PSYCHOTHERAPIST/PSYCHOANALYST

A psychologist is a person who has studied the mind and earned a Ph.D.or Psy.D. Although some definitions state that psychologists have undergone clinical training but cannot prescribe medicines, there are research psychologists who are not engaged in clinical work at all, but merely do experiments to discover how our minds work. Some of their work can concern animal rather than human minds.

A psychiatrist is technically an M.D. specializing in the treatment of mental problems who can prescribe medicines. They are licensed medical doctors, and get irritated when they are called "psychologists" and when psychologists are called "psychiatrists."

Psychotherapist is not a technical term, and may be used by anyone claiming to offer therapy for mental problems. That someone is called a "psychotherapist" tells you nothing about his or her qualifications. But
qualified clinical psychologists and psychiatrists can be properly called "psychotherapists."

A psychoanalyst is a very specific kind of psychotherapist: a licensed practitioner of the methods of Sigmund Freud.

PRESENTLY/CURRENTLY

Some argue that "presently" doesn't mean "in the present." It means "soon." If you want to talk about something that's happening right now, they urge you to say it's going on currently.

POISONOUS/VENOMOUS

Snakes and insects that inject poisonous venom into their victims are venomous, but a snake or tarantula is not itself poisonous because if you eat one it won't poison you. A blowfish will kill you if you eat it, so it is poisonous; but it is not venomous.