adjective. Occurring or completed without perceptible delay.

adjective. Done or made as quickly or directly as possible.

adjective. Present or occurring at a specific instant.

Done or produced in an instant; occurring or acting without any perceptible lapse of time.

In mech., existing in or referring to an instant of time; momentary: as, instantaneous position, displacement, velocity, acceleration, etc. (that is, the position, etc., at any instant).

adjective. Done or occurring in an instant, or without any perceptible duration of time.

adjective. At or during a given instant

adjective. in a plane or in a plane figure which has motions both of translation and of rotation in the plane, is the point which for the instant is at rest.

adjective. in a body which has motions both of translation and rotation, is a line, which is supposed to be rigidly united with the body, and which for the instant is at rest. The motion of the body is for the instant simply that of rotation about the instantaneous axis.

adjective. Occurring, arising, or functioning without any delay; happening within an imperceptibly brief period of time.

adjective. occurring with no delay

"Academic bloggers find that their community of readers often act as fact-checkers or engage the blogger in instantaneous debate over specific points before the book reaches the concretized state of print."

instantaneous axis  instantaneous center of rolling  instantaneous photograph  

fast  

instantaneity  instantaneously  

Aeneas  

abrupt  continuous  immediate  inevitable  momentary  

alert  apt  brief  compact  compendious  

immediate