Witch is the modernization of the old english word Wicce (pronounced which-ay). Which was the word for a male 'wise person' ie. the village sage; usually well versed in herb lore, and the local spiritual traditions. The female varient of the term, wicca, is these days used to refer to a specific type of modern paganism (specifically celtic reconstructionism).
Male 22-30
EDIT: clearing some misconceptions.
a. Witch is gender, and age agnostic.
b. Witch is typically used as a religious indicator. While wicca is typically referential of someone who practices ritual solely for the sake of magic (ie. hipster witches). Some witches would be balk at being called wiccans for that reason.
c. As in b witchcraft is an umbrella term for 2 different things: religion, and ritual. The christian analog would be belief in Jesus, and prayer. Just as not all christians pray, not all people who pray are christians.