Which vocab word is an antonym for cordial?

In which sentence is dishearten used incorrectly?

Sometimes Gary acts like a(n) ________________ in class, but he is actually a very intelligent student.

Fruitless

Inflammable

Hostile

Some hair sprays and paints are ____________________, so do not use them near open flames.

deadly, extremely harmful; evil

unproductive or useless

Bullies can _____________ both physical and emotional damage to their victims.

The tumor was not ________________, so it will not hurt your health.

I was frightened when the ___________ dog growled at me during my nightly run.

The continuous rain this spring __________________ much hardship on the people of the Midwest.

I would not enter a(n) _______ with someone who didn't have the same goals as me.

I am often _______ by people who don't appreciate the freedoms we have as opposed to other places in the world.

The ________ topic of whether or not to make school year round sparks much debate between educators, parents, and students!

An antonym would be to encourage someone

If you understand something, then you are not ______.