When one is deeply uncertain as to how they want to live their life. Often used to describe one who is indecisive and who may have many interests but no specific passions or plans. One who is discertive is often at a cross road in life.
"I'm too discertive to decide what field of study to enter."
"He is clearly a discertious fellow."
Used in reference to something that happen a long while ago. Also used as a hyperbole.
Literal usage: "The same struggles last happened in monochrome to the Roman Empire."
Hyperbolic usage: "Those jeans with that jacket were last seen in monochrome."