The quality of being adaptable; capacity of being adapted or of adapting oneself; potential fitness. (OED 2012)
			
			
				- 1805
 
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This quickness, this plasticity, this adaptability of character is also a feature of the common people in Scotland
					Anonymus (1805). [Rez. Travels from Hamburg, through Westphalia, Holland, and the Netherlands, to Paris. By Thomas Holcroft]. The Annual Review, and History of Literature for 1804 3, 56-69: 64.
				 
				- 1820
 
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the greater developement of his nervous system, the more extensive adaptability of his articulations, the more various mobility of his muscles [of man compared to animals]
					Colburn, H. (1820). Comparative psychology. The New Monthly Magazine 14, 296-304: 301.
				 
				- 1845
 
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One of the most wonderful circumstances in the construction of the hand, is its adaptability to an infinite number of offices
					Todd, R.B. & Bowman, W. (1845). The Physiological Anatomy and Physiology of Man, vol. 2: 149 (as in OED).
				 
				- 1912
 
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The very success of the adaptation decreases the creature’s adaptability
					Huxley, J. (1912). The Individual in the Animal Kingdom: 13.