To recant solemnly; renounce or repudiate: "For nearly 21 years after his resignation as Prime Minister in 1963, he abjured all titles, preferring to remain just plain 'Mr.'"(Time).
To renounce under oath; forswear.
[Middle English abjuren, from Old French abjurer, from Latin abiūrāre : ab-, away; see ab-1 + iūrāre, to swear; see yewes- in Indo-European roots.] ab'ju·ra'tion n., ab·jur'er n.