necessary
//ˈnesəseri//
Adjective
1
Required or needed; essential for a particular purpose or reason.
Water is necessary for all living things.
2
Inevitable or unavoidable as a result of natural law or logic.
Death is a necessary part of life.
Antonym
Noun
1
Something that is essential or required; a basic need or requirement.
Food and water are necessaries for survival.