Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
implācābĭlis (inpl-), e, adj. [2. inplacabilis], unappeasable, implacable (rare but class.); constr. with alicui, in aliquem, and absol.: seque mihi implacabilem inexpiabilemque praeberet, Cic. Pis. 33, 81: implacabilis esse alicui, Liv. 8, 35, 12: in aliquem implacabilis esse, Cic. Fam. 3, 10, 8; Liv. 26, 29, 4: grave et implacabile numen, Ov. M. 4, 452: Turnus, Verg. A. 12, 3: adjuro Stygii caput implacabile fontis, id. ib. 12, 816: caelum, Sil. 17, 253: iracundiae, Cic. Q. Fr. 1, 1, 13, § 39: veteri odio, Liv. 25, 16, 12; Ael. Spart. Vit. Sev. 18.
Adv.: implācābĭlĭter, implacably, only comp.: cui implacabilius irascebatur, Tac. A. 1, 13; so id. H. 3, 53 fin.