When someone's house is empty, or the parents are not home.

cocaine freed from impurities by treatment (as with ether) and heated to produce vapors for inhalation or smoked as crack

Freebase is the final product of a drug (usually cocaine, crack, or heroin) after the adulterants have been removed. This is typically done with a mild acid (for heroin) and ether (for cocaine). The high is much more intense than that of a plain old line. Sadly, its effects are short lived.

n. a form of cocaine similar to crack. it is usually smoked. also spelled as two words free base.
v. to smoke freebase

Freebasing is when you take chemical reagents, research chemicals, or drugs, and you turn them from the HCl salt or other salts to the freebase. This is often done either with baking soda and hydrogen oxide(water) or sodium hydroxide. Sometimes you need to freebase something to react with ketones or aldehydes in a lab to form an imine. Sometimes you freebase something to smoke it(make it more smokable) even though it last shorter just because the high or buzz hits faster. HCl salts can be mixed in water and drinked or snorted. Freebase can only be smoked. Ethylamine HCl in ethanol solution to freebase ethylamine in ethanol using sodium hydroxide. Methylphenidate HCl (Ritalin, MPH HCl) to freebase Methylphenidate. 4F-MPH HCl to freebase 4F-MPH. Troparil HCl to freebase Troparil. Amphetamine HCl to freebase Amphetamine. Ethylamphetamine HCl to freebase Ethylamphetamine. Cocaine HCl to freebase Cocaine(called crack). 3-FA HCl to freebase 3-FA. Blue speed HCl to freebase Blue speed.

The act of smoking a drug freebase. "Freebase" refers to the non-salt form of a drug. Drugs are usually converted to a water soluble salt so that they can be orally or intranasally consumed. The term "freebase" has nothing at all to do with the purity or potency of a drug.

For example, cocaine powder is cocaine hydrochloride, a water soluble salt. Being water soluble means that you can snort it, eat it, inject it, or plug it (put it up your ass) and you will get high. However, a cruder form of cocaine is cocaine freebase (i.e. crack), which is not water soluble and therefore cannot bet eaten or snorted. You must smoke it to feel the effects.

It's the same with methamphetamine. Meth freebase is an oily liquid, which your body cannot absorb, so the only way to get high from it is to smoke it. Crystal meth, however, has been converted to a water soluble salt, and can therefore be snorted, injected, etc.

The heat used to smoke freebase drugs generally destroys a large amount of the active drug you are trying to consume, therefore it is NOT an efficient route of administration. However, the high generally has a faster onset, and the physical act of smoking is generally pleasurable, so that's why we have people becoming addicted to crack. The duration from smoking crack is much shorter than the duration from snorting coke, but again, people like smoking things, so people enjoy crack. You'll actually get higher for longer if you snort cocaine hcl vs. smoking crack.

FreeBASIC - as the name suggests - is a completely free, open-source, 32-bit BASIC compiler, with the syntax the most compatible possible with MS-QuickBASIC, that adds new features such as pointers, unsigned data types, inline-assembly and many others.

Inhaling the fumes from when you light a fire under crushed up pills.

"freebasing" is typically referring to the act of smoking drugs, such as cocaine or heroin, most likely in a purified/concentrated form known as freebase (an example would be crack form of cocaine)
Apparently it produces an intense high quickly, but the effects typically do not last very long.