。
She accused me of being a liar.
Literal
She [topic-は] me [object-を] liar [as-だと] accused.
The Xを Yだと非難する ('accuse X of being Y') frame uses を for the accused, the copula だ, and quotative と for the content of the accusation. うそつき ('liar') is a compound noun built from 嘘 ('lie') + つき (the masu-stem of つく, 'to attach, to do, to tell' — as in 嘘をつく 'tell a lie'). The pattern noun + verb-stem is highly productive: 嘘つき ('liar'), 落書き ('graffiti, doodle' from 落書く), 物書き ('writer'). 非難する is the heavy formal verb for accusation/condemnation.