Full Idea
A definition is the easiest of all things to destroy; for, since it contains many assertions, the opportunities which it offers are very numerous, and the more abundant the material, the more quickly the reasoning can set to work.
Gist of Idea
Definitions are easily destroyed, since they can contain very many assertions
Source
Aristotle (Topics [c.331 BCE], 155a03)
Book Reference
Aristotle: 'Posterior Analytics and Topica', ed/tr. Tredennick,H/Forster,ES [Harvard 1960], p.671
A Reaction
I quote this to show that Aristotle expected many definitions to be very long affairs (maybe even of book length?)