The Collaborative International Dictionary of English v.0.48:
Agreeability \A*gree`a*bil"i*ty\, n. [OF. agreablete.] 1. Easiness of disposition. [Obs.] --Chaucer. [1913 Webster] 2. The quality of being, or making one's self, agreeable; agreeableness. --Thackeray. [1913 Webster]WordNet (r) 3.0 (2006):
agreeability n 1: a temperamental disposition to be agreeable [syn: agreeableness, agreeability] [ant: disagreeableness]