1.

espionage

Espionage always happens in the open.

In industrial espionage, companies try to discover the secrets of their competitors.

Cheating is espionage by another name.

2.

intrigue

Military dictatorships typically start with an intrigue by a handful of officers to overthrow the current government.

The owner intrigued her family to help her get the new restaurant off to a good start.

An intrigue is a plan gone bad.

3.

covert

The mayor made his plan covert in order to win over as many people as possible.

Many a scandal in government begins with a covert action that has become public knowledge.

Companies often offer rebates to their most covert customers.

4.

guise

The guise of a person is his or her very soul.

In the first scene, the hero appears in a guise that makes him unrecognizable.

By now, I have so many guises in my closet that it takes forever to decide what I should wear in the morning.

5.

pseudonym

A pseudonym is a name consisting of a single word, like "Madonna."

Illness is a pseudonym for disease.

Performing artists usually adopt a pseudonym if they think their real names sound funny or are hard to pronounce.

6.

illicit

When members of the congregation discovered that their pastor was having an illicit affair, they were deeply shocked and hurt.

A fugitive from justice, he did not dare use his illicit name when he booked the room because that would have made it easy for the police to discover his whereabouts.

His illicit voice suggested a man who had a gift for romance.

7.

cache

I ran out of cache and had to go to the bank.

King Tut's tomb was one of the most spectacular caches of precious objects ever found.

She has turned her living room into the most stunning cache in the house, with pieces of art displayed on every surface.

8.

pretext

Pretext and pretense are closely related in meaning.

The salesman pretexted that the car he was showing the couple was the last one on the lot.

The journalist insisted on offering the scientist a pretext of the questions she was going to ask.

9.

stealth

The detective approached the house stealthily, using shrubs and hedges for cover.

Obtaining something by stealth means obtaining it illegally.

The stealth displayed by the player was just wonderful to watch.

10.

cryptic

After a wild youth, he retired to the mountains to become a cryptic.

Explain yourself and be more cryptic!

Many prophecies are so cryptic that one can read almost anything into them.