The spelling of "waxy spleen" can be confusing because it contains the letter "x," which can make it difficult to know which sound it represents. In IPA phonetic transcription, the word is spelled /ˈwæksi splin/, which shows that the "x" represents the two sounds of "ks" together. The "a" is pronounced like the "a" in "cat," and the "y" makes the long "e" sound. The word refers to a hardened, fatty spleen that can occur in certain medical conditions.
Amyloid degeneration of the spleen.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.