emasculate

from The American Heritage® Dictionary of the English Language, 5th Edition.

• transitive verb To castrate.
• transitive verb To deprive of strength or vigor; weaken.
• adjective Deprived of virility, strength, or vigor.

from The Century Dictionary.

• Deprived of the male functions; castrated; hence, unmanned; deprived of vigor.
• In plant-breeding, to remove the anthers from a hermaphrodite flower in order to prevent self-fertilization. In case of monœcious plants, as Indian corn, the whole male inflorescence is removed. See detasseling.
• To deprive of the male functions; deprive of virility or procreative power; castrate; geld.
• To deprive of masculine strength or vigor; weaken; render effeminate; vitiate by unmanly softness.
• In general, to weaken; destroy the force or strength of; specifically, to weaken or destroy the literary force of, as a book or other writing, by too rigid an expurgation, or by injudicious editing.
• To become unmanned or effeminate.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To deprive of virile or procreative power; to castrate power; to castrate; to geld.
• transitive verb To deprive of masculine vigor or spirit; to weaken; to render effeminate; to vitiate by unmanly softness.
• adjective Deprived of virility or vigor; unmanned; weak.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective Deprived of virility or vigor; unmanned; weak.
• verb transitive To deprive of virile or procreative power; to castrate; to geld.
• verb transitive To deprive of masculine vigor or spirit; to weaken; to render effeminate; to vitiate by unmanly softness.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb remove the testicles of a male animal
• adjective having unsuitable feminine qualities
• verb deprive of strength or vigor