Early 17th century; earliest use found in John Floyd (1572–1649), Jesuit and religious controversialist. From admirable + -ity, after classical Latin admīrābilitās wonderful character, remarkableness, admiration, wonder.
Definition of admirability in US English:
admirability
nounˌadm(ə)rəˈbɪlɪti
1The quality of being admirable; = admirableness.
2In plural Admirable things or qualities.
Origin
Early 17th century; earliest use found in John Floyd (1572–1649), Jesuit and religious controversialist. From admirable + -ity, after classical Latin admīrābilitās wonderful character, remarkableness, admiration, wonder.