Depilation means hair removal.  Strictly, "pilus" is Latin for hair and putting the "de" in front of it, in medical terminology, means to deprive or be rid of.  Putting "ation" at the end of the word, in English, makes it into an action.

Why would we want to remove hair?

Many cultures in the world have different attitudes to hair.

Most cultures not only tolerate hair on the head, but make it into a feature.  Different haircuts, styles and colours are used to attract members of the opposite sex and denote social status and wealth.  In some cultures, or in some societies, haircuts can also show allegiance to different sects, groups or gangs.

Attitudes to body hair and vary between the sexes, different cultures and personal taste. In many western cultures, females remove hair from all areas of the body and face with the exception of the scalp, eyebrows and usually pubic hair-although this is often shaped or reduced. Attitudes to under-arm hair (axillary hair) are very variable with some cultures tolerating it and others abhoring it.

Males tend to be more tolerant of hair growth, although trends in Western societies are changing with younger males often undergoing hair removal procedures for body hair.