This is not very clear.
What it means in court is that if you destroy evidence, it can be presumed that it contained evidence detrimental to your case.
Legal, medical and scientific terms can get specialized..................
More Definitions for spoliation:
spoliation noun
spo·li·a·tion | \ ˌspō-lē-ˈā-shən \
Legal Definition of spoliation
1: the destruction, alteration, or mutilation of evidence especially by a party for whom the evidence is damaging
2: alteration or mutilation of an instrument (as a will) by one who is not a party to the instrument