Definition of: instant

(in′stənt) adjective
1. Immediately impending.
2. Now passing; current; present: the 10th instant (the 10th day of the month now passing). See PROXIMO, ULTIMO.
3. Direct; immediate.
4. Eager and active; urgent; importunate. See synonyms under IMMEDIATE.
—noun
1. A particular point of time; the moment which in passing may be called now.
2. A very brief portion of time; moment.
—adverb Poetic Instantaneously; instantly. [<OF <L instans, -antis, ppr. of instare stand near, urge <in- upon + stare stand]