backslide, backside, back side

Backslide or backslide means to return to a former bad habit, to relapse into a vice one had given up --
He's afraid that he'll backslide if he misses a meeting.
The temptation to backslide is too great; he won't come to the party.

Backside or backside ( one word ) means behind or rear end, the one you sit on --
He fell right on his backside, but he wasn't hurt.
Your backside is peeking out of the bottom of your suit.

Back side or back side ( two words ) means the rear or reverse side of a thing --
There is graffiti on the back side of the billboard.
The back side of the fence is covered with vines.

Now that you know that, you can say --
"On the back side of the page, explain what makes you want to backslide."
"Someone has painted a bare backside on the back side of the wall."

corporate, cooperate

Corporate or corporate describes something related to an association, one regarded as a single entity for legal purposes --
Our corporate charter requires us to have an annual meeting.
He hopes to climb the corporate ladder, to be an executive.

Corporate may describe the main governing body of a business, its head office --
We have some new regulations, sent from corporate headquarters.
He's the only corporate executive who doesn't want to see this branch office closed.

Cooperate or cooperate ( also spelled coöperate or co-operate ) means to work or act together, or to be willing to work or act with others; to go along with the program --
If we all cooperate, the work will be done in an hour or two.
He won't cooperate, even when all of the others are getting along.

Now that you know that, you can say --
"We will improve our corporate culture if we all cooperate with the new director."

courier, currier

Courier or courier means someone who travels to deliver papers, a package, or news --
A courier will deliver the documents; you'll have to sign for them.
He sent a letter by special courier; it will be there this afternoon.

Currier or currier ( rhymes or nearly rhymes with courier ) means someone who dresses ( soaks, scrapes, dyes ) leather, or someone who combs and rubs down a horse --
He's a currier; he buys tanned leather and dresses it for making bags and jackets.
The currier said the horse seemed very nervous today.

Currier may also mean someone who flatters to gain favor with a boss or person in authority --
He is a sycophant; a currier-of-favor.

Now that you know that, you can say --
"The currier will take care of the horse while the courier delivers his message to the general."

cocaine, Cockaigne

Cocaine or cocaine means a drug made from coca leaves, once used as a local anesthetic, now an illegal drug in the United States --
The police charged him with possession of cocaine.
He has a cocaine habit; I don't know how he can afford it.

Cockaigne ( always capitalized, sometimes spelled Cockayne ) means a make-believe land of plenty with no work --
He has no plans for the future; he thinks he's going to live in the land of Cockaigne.
This new job seems like the land of Cockaigne to him.

Now that you know that, you can say --
"Under the influence of cocaine, he writes nonsensical stories about life in Cockaigne."

virtuous, virtuoso

Virtuous or virtuous means morally good or upright --
He endeavored to remain virtuous; he threw himself into his work when he was tempted to backslide.
His sermons about virtuous conduct were often ignored.

Virtuoso or virtuoso means an excellent or extraordinary musician, able to play the most difficult compositions --
He was considered a virtuoso at a young age, before he was thirty.
This is a virtuoso piece, of interest mainly to other musicians.

Now that you know that, you can say --
"The young piano virtuoso was virtuous, even though he found the violinist alluring."

commander, commandeer

Commander or commander means a person in authority, most commonly meaning military authority; a naval officer below the rank of captain --
The President of the United States is also the Commander in Chief of the armed forces.
He was a commander when he retired from the navy.

Commandeer or commandeer means to take private property for military use --
We'll have no way to get back to our unit unless we can commandeer a truck.
Explain to them that we'll need to commandeer their house for our headquarters.

Now that you know that, you can say --
"The commander wants us to commandeer any small boats in the area."

uncharted, unchartered

Uncharted or uncharted means not shown on a map or chart; new and unexplored territory, literally or figuratively --
This area is still uncharted, so we'll need to use a compass to find our way.
No one has tried this before; it will be uncharted territory.

Unchartered or unchartered means without a set of rules or laws; without official or legal authorization --
This city is unchartered; the legislature hasn't recognized it.
It's an uncharted corporation;  the board will meet soon to discuss a set of regulations.

Now that you know that, you can say --
"This startup is unchartered; setting up its board will be uncharted territory."