unsaponifiable
adjective
un·sa·pon·i·fi·able
| \ -sə-ˌpän-ə-ˈfī-ə-bəl
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Medical Definition of unsaponifiable
: incapable of being saponified
—used especially of the portion of oils and fats other than the glycerides
unsaponifiable fractions such as steroids or vitamin A