Definify.com
Webster 1913 Edition
Immitigable
Im-mit′i-ga-ble
,Adj.
 [L. 
immitigabilis
; fr. pref. im- 
not + mitigare 
to mitigate.] Not capable of being mitigated, softened, or appeased. 
Coleridge.
 Webster 1828 Edition
Immitigable
IMMIT'IGABLE
,Adj.
 Definition 2025
immitigable
immitigable
English
Adjective
immitigable (comparative more immitigable, superlative most immitigable)
-  That cannot be mitigated
-  1851, Herman Melville, Moby-Dick, Chapter 41, 
- He was intent on an audacious, immitigable, and supernatural revenge.
 
 -  1887, Benvenuto Cellini, Autobiography, translated by John Addington Symonds, New York: P.F. Collier & Son, 1910, Chapter XXXIX, p. 81, 
- "Oh, my dear son, the plague in this town is raging with immitigable violence, and I am always fancying you will come home infected with it. […] "
 
 -  1949, Peter de Vries, The Tunnel of Love, New York: Popular Library, 1978, Chapter 13, p. 149,
- " […] Matter is running down and the universe itself will one day become extinct. An everlasting and immitigable nothingness, in the void of black and absolute−"
 
 
 -  1851, Herman Melville, Moby-Dick, Chapter 41,