1520s, "mortal thing or substance;" 1560s, "a human being" (as subject to death); from mortal (adj.). Latin mortalis also was used as a noun, "a man, mortal, human being."
From 1832 in reference to "intelligent study and appreciation of the classics," especially in reference to the Renaissance. By 1847 in reference to "system or mode of thought in which human interests predominate" (originally often in the writings of its enemies). As a pragmatic system of thought, defined 1907 by co-founder F.C.S. Schiller as "The perception that the philosophical problem concerns human beings striving to comprehend a world of human experience by the resources of human minds."
1580s, "student of the classical humanities, one accomplished in literature and classical culture," from French humaniste (16c.), formed on model of Italian umanista "student of human affairs or human nature," coined by Italian poet Lodovicio Ariosto (1474-1533), from Latin humanus "human" (see human (adj.).
In this use, the original notion appears to be "human" as opposed to "divine," that is, a student of the human achievements of the pre-Christian authors and philosophers, as opposed to the theological studies of the divines. As "this new-old learning had, or was credited with, a tendency to loosen the hold of the Church upon men's beliefs," humanist also gradually came to mean "free-thinker" [Fowler]. Philosophical sense is from 1903, from Comte's Religion of Humanity (compare humanism), unconnected to the two earlier meanings, "though accidentally near one of them in effect" [Fowler].
"action of holding back (action or motion); that which restrains, a check, hindrance," early 15c., restreinte, from Old French restreinte, noun use of fem. past participle of restraindre (see restrain).
Specifically in reference to refractory prisoners or dangerous lunatics by 1829. The sense of "reserve, repression of extravagance in manner or style" is from c. 1600. Phrase restraint of trade is by 1630s.
Wherever thought is wholly wanting, or the power to act or forbear according to the direction of thought ; there necessity takes place. This, in an agent capable of volition, when the beginning or continuation of any action is contrary to that preference of his mind, is called compulsion ; when the hindering or stopping any action is contrary to his volition, it is called restraint. [Locke, "Of Human Understanding"]
Homo as the genus of the human race, within the order Primates, was formally instituted in Modern Latin 1758 by Linnaeus (originally also including chimpanzees). Used since in various Latin or pseudo-Latin combinations intended to emphasize some aspect of humanity, as in Henri Bergson's Homo faber "man the tool-maker" (in "L'Evolution Créatrice", 1907).