IPA: /səˈstɛntətɪv/
KK: /səˈstɛntəˌtɪv/
Designed to support or maintain something, often in a way that provides strength or stability.
The sustentative evidence helped to strengthen the argument in the debate.
Sustentative → It is formed from "sustinere" (meaning to hold up or support) and the suffix "-ive" (meaning having the nature of). The word "sustentative" refers to something that has the nature of supporting or sustaining.
Think of something that 'holds up' or 'supports' ('sustinere') — that's why sustentative means having the quality of support.