tiptoe

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

• intransitive verb To walk or move quietly on one's toes.
• noun The tip of a toe.
• adjective Standing or walking on one's toes.
• adjective Stealthy; wary.
• adverb On one's toes.
• adverb Stealthily; warily.
• idiom (on tiptoe) Full of anticipation; eager.

from The Century Dictionary.

• To go or move on the tips of the toes, or with a mincing gait, as from caution or eagerness.
• noun The tip of a toe: used in the plural, with reference to posture or movement on the ends (balls) of the toes of both feet, literally or figuratively.
• noun The ends of the toes collectively; the forward extremity of the foot, or of the feet jointly: in the phrase on tiptoe (a tiptoe), indicating cautious or mincing movement, or a stretching up to the greatest possible height: also used figuratively.
• On tiptoe, literally or figuratively.

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

• adjective Being on tiptoe, or as on tiptoe; hence, raised as high as possible; lifted up; exalted; also, alert.
• adjective Noiseless; stealthy.
• adjective the highest degree of mirth.
• intransitive verb To step or walk on tiptoe.
• noun The end, or tip, of the toe.
• noun to be awake or alive to anything; to be roused; to be eager or alert.

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

• verb Alternative spelling of tip-toe.
• noun The tips of one's toes collectively.

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

• adjective walking on the tips of ones's toes so as to make no noise
• verb walk on one's toes
• adverb on tiptoe or as if on tiptoe
• noun the tip of a toe