[tip.toe] n (14c): the position of being balanced on the balls of the feet and toes with the heels raised--usu. used with on; also: the ends of the toes -- on tiptoe : alert, aroused "the contest of skill that puts one on tiptoe to win --Deerfield (Wisc.) Independent"
[2]tiptoe adv (1592): on or as if on tiptoe [3]tiptoe adj (1593) 1: standing or walking on or as if on tiptoe
2: cautious, stealthy [4]tiptoe vi tip.toed ; tip.toe.ing (ca. 1661) 1: to stand or raise oneself on tiptoe
2: to walk or proceed quietly or cautiously on or as if on tiptoe