。
She has nothing but contempt for liars.
Literal
She [topic-は] lie [object-を] tell people [object-を] despises.
嘘をつく ('to tell a lie') is a fixed collocation; the verb つく here is a reading of 吐く ('to spit out / utter') — the same morpheme behind 息をつく ('catch one's breath') and 悪態をつく ('to curse'), all framing what is said as something expelled from the mouth. The kana spelling つく is the standard today, but 嘘を吐く still appears in literary writing. The relative clause 嘘をつく ('who tell lies') sits before 人間 ('person, human') with no relative pronoun. 軽蔑する ('to despise') is a Sino-Japanese verb of strong feeling, formal enough that it sits naturally in writing or principled declarations rather than light conversation. 人間 here is broader than 人 ('person'); it carries an abstract or essentialist nuance — 'people of that kind, humans who do that.'