an infinitesimal or very short space of time; a moment

They arrived not an instant too soon.

the point of time now present or present with reference to some action or event.

a particular moment

at the instant of contact.

a food or beverage, esp. coffee, specially processed for quick preparation.

Older Use . the present or current month.

succeeding without any interval of time; prompt; immediate

instant relief from a headache.

pressing or urgent

instant need.

noting a food or beverage requiring a minimal amount of time and effort to prepare, as by heating or the addition of milk or water, before being served or used

instant coffee; instant pudding.

occurring, done, or prepared with a minimal amount of time and effort; produced rapidly and with little preparation

an instant book; instant answers; instant history.

designed to act or produce results quickly or immediately

an instant lottery.

Older Use . of the present month: your letter of the 12th instant. Abbreviation

inst. Compare proximo ultimo

present; current

the instant case before the court.

instantly.

adjective

delayed , eventual , late , later

adjective

burning * , clamant , contemporary , crying * , current , dire , direct , exigent , existent , extant , fast , imperative , importunate , insistent , instantaneous , on-the-spot , present , present-day , pressing , prompt , quick , split-second , immediate , crying , emergent , urgent , momentary , simultaneous

noun

bat of the eye , breath , crack , flash , jiffy * , juncture , minute , nothing flat , occasion , point , sec , second , shake * , short while , split second * , tick , time , trice , twinkling * , while , wink * , moment , twinkle , twinkling , wink , direct , fast , immediate , instantaneity , jiffy , pressing , quick , rapid , simultaneity , speedy , swift , urgent

adverb

forthwith , immediately , instantly , now , right away , right off , straightaway , straight off