The Human condition was the sum total of Human experience, thought, status, and ability.
In 2152, an irate Jonathan Archer informed the Wisp that had seized control of Malcolm Reed, "Let's see how much you enjoy experiencing the Human condition locked in Reed's quarters." (ENT: "The Crossing")
In 2269, upon learning of his impending death, Flint told Doctor Leonard McCoy that his desire was to expend his remaining time and talents upon improving the Human condition. (TOS: "Requiem for Methuselah")
In 2366, Data sought to learn about the Human condition through participating in holodeck re-creations of William Shakespeare's plays. Jean-Luc Picard noted that he would do well to interpret the roles he assumed in his own style, not that of other actors. (TNG: "The Defector")
According to Alixia, who had spent considerable time studying the Human condition, by 2370, Humans on the whole had "become fat and lazy and dull" and that "the common conceit that the Human species has evolved over the last several centuries is ludicrous. What gains we have made have come at the cost of our own core identities. Man has lost touch with his true power." (this told by Benjamin Sisko to Miles O'Brien. (DS9: "Paradise")
That year, following Data's takeover by the D'Arsay archive, Picard noted that the Soong-type android had "had an experience that transcends the Human condition. You have been an entire civilization." (TNG: "Masks")