Disguise

Disguises item of clothing that will allow you to slip past guards but if you come across someone who actually wears those clothes after a short amount of time they will trigger an alarm. By behaving suspiciously you can also cause gaurds to attack you so don't roll, punch, crawl in front of a guard. Having a bloodied disguise or walking into a guard will also raise suspicion. The exception to this is Raikov Disguise this allows you to attack anyone and get away with it.

On being discovered it can be quite possible to have guards run right past you once the alert level comes down.

the main problem with disguises is that most of snakes weapons become disabled this makes it difficult to fight back when you are discovered.

There are also special actions that can be performed while wearing a disguise. these can be performed by pressing the action button.

Weapons
these are the weapons that can be used while disguised.
 * Handkerchief
 * Cigarettes

Disguises

 * Officer - special action: salute
 * Scientist - special action: adjusts glasses
 * Maintenance

Masks

 * Mask - This is an advanced mask that was designed by the CIA to look like Soviet Officer Ivan Raidenovitch Raikov. At the start of the virtuous mission Snake asks the Major what he should do if he should run into the guy. The Major tells him to beat him up.
 * Monkey Mask - A mask that looks like a monkey (Monkey From Ape Escape). To unlock, complete all Snake vs Monkey levels. Can be worn during cutscenes but covers snakes eyes so he can not see during cutscenes.
 * Croc Cap - A crocodile-shaped cap. Its most useful in water; wearing this while swimming helps make guards ignore Snake. The Croc cap also scares fishes away.