Definition of "instinct" []

• An inborn pattern of behavior that is characteristic of a species and is often a response to specific environmental stimuli: the spawning instinct in salmon; altruistic instincts in social animals. (noun)
• A powerful motivation or impulse. (noun)
• An innate capability or aptitude: an instinct for tact and diplomacy. (noun)
• Deeply filled or imbued: words instinct with love. (adjective)
• Obsolete Impelled from within. (adjective)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Thus, if we consider only those typical cases in which the complete triumph of intelligence and of instinct is seen, we find this essential difference between them: _instinct perfected is a faculty of using and even of constructing organized instruments; intelligence perfected is the faculty of making and using unorganized instruments_."
• "Let us adopt then words sanctioned by usage, and give the distinction between intelligence and instinct this more precise formula: _Intelligence, in so far as it is innate, is the knowledge of a_ form; _instinct implies the knowledge of a_ matter."
• "Once upon a time, the term instinct was perfect way to explain things that we didn't completely understand at the time."