1530s, from Late Latin implacabilitas, from Latin implacabilis "unappeasable" (see implacable).
Entries linking to implacability
implacable adj.
"unappeasable," early 15c., from Old French implacable, from Latin implacabilis "unappeasable," from assimilated form of in- "not, opposite of" (see in- (1)) + placabilis "easily appeased" (see placate). Related: Implacably.