Observative is a totally real word that is most definitely not made up. It can be used to describe someone who is making an observation and therefore can be described as observative.
Person 1: "Yep, this cry is Magmortar's and not Volcanion's."
Person 2: "Woah, you're so observative!"
The period of time when you’re casually fucking a guy you used to date, and you’re assessing whether or not he has the emotional capacity to potentially be in a relationship with again, and if you even want to try to be anything other than friends who have great sex rock out and celebrate life a couple times a month. Also, it’s so much fucking fun and you don’t want that to stop or change so it’s an excellent way to maximize the fun, to stretch out the observation period. This amount of time is unspecified. Most likely lasts as long as it takes for one of the parties involved to freak out.
Michael, I didn’t say I wanted you to be my boyfriend?! This is still the observation period, I’m observing you, and you are observing me too, really.
Paul awoke the morning of his 60th birthday and examined his face closely in the mirror. Laughing wryly at the sight, he vowed never to perform that act again. Observational humor, in this case, only went so far.
An initial observation is the measurement that you take before you start any process that might cause a change. When you compare your subsequent observations with the initial one, you will see whether any change has taken place, and you will be able to measure the change.
The coach's Initial observation to his players will help him find out about the strengths and weaknesses of his players.