IPA: //nɒnˌɛstəˈrɪfaɪd//
KK: /nɑnˌɛstərɪˈfaɪd/
Not having undergone esterification, meaning it has not formed esters with acids or alcohols.
The nonesterified fatty acids are important for various metabolic processes.
Nonesterified → It is formed from "non-" (meaning not), "ester" (from Latin "aestas", meaning summer, referring to the chemical compound formed from an acid and an alcohol), and "-ified" (meaning to make or to become). The word describes a state of not being converted into an ester.
Think of 'not' ('non-') being related to a chemical compound ('ester') that hasn't been changed or made into something else.