-ability or -ibilitysuff. Ability, inclination, or suitability for a specified action or condition: teachability.[Middle English -abilitie, from Old French -abilite, from Latin -?bilit?s, from -?bilis, -able.]American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.a?bil?i?ty (??b?l ? ti) n., pl. -ties. 1. power or capacity to do or act physically, mentally, legally, morally, or financially. 2. competence based on natural skill, training, or other qualification. 3. abilities, talents; special skills or aptitudes. [1350?1400; Middle English (h)abilite