"Sustinance" is probably misspelled. Trying sustenance instead Definition of sustenance
sustenance has definitions from the field of food
1
[ noun ] (food) a source of materials to nourish the body
2
[ noun ] the financial means whereby one lives

Examples

"each child was expected to pay for their keep" "he applied to the state for support" "he could no longer earn his own livelihood"

3
[ noun ] the act of sustaining life by food or providing a means of subsistence

Examples

"they were in want of sustenance" "fishing was their main sustainment"

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