instantaneous

adjective

1. occurring, done, or completed in an instant: an instantaneous response.
2. existing at or pertaining to a particular instant: the instantaneous position of the rocket.

adjective

1. occurring with almost no delay; immediate
2. happening or completed within a momentinstantaneous death
3. maths
   1. occurring at or associated with a particular instant
   2. equal to the limit of the average value of a given variable as the time interval over which the variable is considered approaches zeroinstantaneous velocity