The punitive silences,
the bad atmosphere they generate,
the mind-games they use to try to **** you in
are telltale signs of the toxic person.
It could be your in-laws, a parent, coworker, your boss or spouse,
a sibling, a roommate, boyfriend or girlfriend,
someone you want out of the house.
Toxic people want to make you miserable.
Especially if you're a decent sort, they hone in on you like a heat-seeking missile.
They spew their negativity and blame it on you.
They lie constantly, or twist the facts to suit their changing needs of the moment
and they never apologize (so don't expect an apology, ever).
With a toxic person there is no reciprocity.
They sprinkle their toxic dust on you.  It makes them feel better.
Their ulterior goal is to demean you, to make you feel smaller.
They project their worst tendencies onto you,
find fault with you for traits you don't possess---
a shadow of the **** that lurks inside them.
They try to dictate the emotional atmosphere
through their attitude or twisted mood.
They drain you of your energy, bring you down,
They'll always find a reason why your good news isn't great news.
Their agenda is to cut you down to their size,
to manipulate and control
to ******* over while they play the injured party.

Confront the bully.  Speak up to the manipulator, the trickster, the backstabber.
but beyond a certain point
there is no point in arguing with them.  
Don't try to change the toxic person.  You can't.
You'd have better luck changing an orangutan into **** sapiens.
Only a shrink could change them, and then only if they hit rock-bottom.
Don't try to justify yourself.  It's a waste of time which would only draw you deeper into their net.
Set boundaries to keep their negativity in check.
Stop trying to please them.
Let that toxic somebody in your life know you're onto them
and they can't get away with it anymore.
Don't fall into their trap, don't get caught up in their life-dramas
or try to get them out of trouble.  Don't let them instill guilt in you.
But try not to take their toxicity personally.
Remember, it's them, not you.  You are not to blame
though they desperately want you to feel you've done something wrong.

If necessary (and if possible), delete the toxic person from your life and move on.
Know when enough is enough.
Saying good riddance doesn't necessarily mean you hate them, it means
your own well-being comes first.
Immunize yourself.  Preserve your inner strength.
Set your own rules.
And, when possible, just walk away.