adverb, adjective

standing or walking on tiptoe (usually used predicatively).
eagerly expectant, as anticipating a desired event or arrival: waiting atiptoe for the mail.
moving with caution or stealth, as avoiding calling attention to one's presence: She walked atiptoe through the sleeping house.

Origin of atiptoe

First recorded in 1570–80; a-1 + tiptoe Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019