May I Cut In?: Backstab an enemy and the Medic healing him within 10 seconds of each other.

On Her Majesty's Secret Surface: Start capping a capture point within a second of it becoming available.

Point Breaker: Kill 15 enemies who are standing on a control point they own.

Sap Auteur: Destroy 1000 Engineer buildings with sappers.

Sapsucker: Sap an enemy building, then backstab the Engineer who built it within 5 seconds.

Skullpluggery: Headshot 20 Snipers with the Ambassador.

Slash and Burn: Backstab an enemy, who then switches to Pyro before they respawn.

Sleeper Agent: Kill an enemy who triggered your feign death in the last 20 seconds.

Spies Like Us: While cloaked, bump into an enemy cloaked Spy.

Spymaster: Backstab 1000 enemies.

The Man from P.U.N.C.T.U.R.E.: Stab an enemy while fencing.

The Man with the Broken Guns: Backstab an Engineer, then sap 3 of his buildings within 10 seconds.

The Melbourne Supremacy: Dominate a Sniper.

Triplecrossed: Backstab 3 Snipers in a single life.

Wetwork: Stab an enemy to death while under the influence of Jarate.

Who’s Your Daddy?: Headshot 3 Scouts with the Ambassador.

You Only Shiv Thrice: Backstab 3 enemies within 10 seconds.

A Cut Above: Kill a gun-wielding Spy with your knife.

Agent Provocateur: Backstab your Steam Community friends 10 times.

Burn Notice: Survive 30 seconds after being ignited while cloaked.

Come in From the Cold: Get a Revenge kill with a backstab.

Constructus Interruptus: Kill an Engineer who is working on a sentry.

Counter Espionage: Backstab a disguised Spy.

Deep Undercover: While using the Cloak and Dagger, kill the same enemy 3 times, all within the same area in a single life.

Die Another Way: Kill a Sniper after your backstab breaks his Razorback.

Diplomacy: Kill 50 enemies with the Ambassador.

Dr. Nooooo: Backstab a Medic that is ready to deploy an ÜberCharge.

For Your Eyes Only: Provide an enemy with a freezecam shot of you flicking a cigarette onto their corpse.

FYI I am a Spy: Backstab a Medic who has healed you in the last 5 seconds.

High Value Target: Backstab an enemy who is dominating 3 or more of your teammates.

Identity Theft: Backstab the enemy that you're currently disguised as.

Insurance Fraud: Kill an enemy while you're being healed by an enemy Medic.

Is It Safe?: Backstab 50 enemies who are capturing control points.

Joint Operation: Sap an enemy sentry within 3 seconds of a teammate sapping another.

UNLOCKED - Welcome to the internets:  Fail to understand what 'Private' means on YouTube.