willing

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

• adjective Disposed or inclined; prepared.
• adjective Acting or ready to act gladly; eagerly compliant.
• adjective Done, given, or accepted voluntarily or ungrudgingly. synonym: voluntary.

from The Century Dictionary.

• noun Inclination; desire; intention.
• Favorably disposed; ready; inclined; desirous: as, willing to work; willing to depart.
• Voluntary; cheerfully given, granted, done, or borne: as, willing service; willing poverty.
• Characterized by promptness or readiness in action; free from reluctance, laziness, or slowness: willing horse; a willing hand.
• In harmony or accord; like-minded.
• Synonyms Minded.
• Spontaneous, etc. See voluntary.

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

• adjective Free to do or to grant; having the mind inclined; not opposed in mind; not choosing to refuse; disposed; not averse; desirous; consenting; complying; ready.
• adjective Received of choice, or without reluctance; submitted to voluntarily; chosen; desired.
• adjective rare Spontaneous; self-moved.

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

• adjective Ready to do something that is not (can't be expected as) a matter of course.
• noun The execution of a will.
• verb Present participle of will.

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

• adjective disposed or inclined toward
• noun the act of making a choice
• adjective not brought about by coercion or force