1 Renounce or reject (something desired or valuable); to refuse or deny oneself (some rights, conveniences, etc.); reject; renounce.
2 to relinquish; give up.
The fact of so little cultivation does not abnegate the existence of industry on the part of the villagers. (Mayne Reid, The War Trial)
Yet Portugal under António Costa has proved a model of fiscal rectitude, while making tough decisions to clean up the banking system. (Neil Mackay, Why Scotland is just rubbish at recycling, The Herald, 2019)
In those days the strong made no pretence to protect the weak, or to abnegate their natural power. (Richard Jeffries, Hodge and His Masters)
There's no denying that the Latin root negare has given English some useful words. That verb, which means 'to deny,' is the ultimate source of the noun 'abnegation,' a synonym of 'denial' that began appearing in English manuscripts in the 14th century. By the 17th century, people had concluded that if there was a noun 'abnegation,' there ought to be a related verb 'abnegate,' and so they created one by a process called 'back-formation' (that's the process of trimming a suffix or prefix off a long word to make a shorter one). But 'abnegate' and 'abnegation' are not the only English offspring of 'negare.' That root is also an ancestor of other nay-saying terms such as 'deny,' 'negate,' and 'renegade.' (MerriamWebster)
'deny (something) to oneself,' 1650s, from Latin abnegatus, past participle of abnegare 'to refuse, deny,' from ab 'off, away from' + negare 'to deny,' from PIE root ne- 'not.' (Online Etymological Dictionary)