What does Vaishnavi mean?
From the Sanskrit वैष्णवी (vaiṣṇavī), feminine of Vaishnava, 'relating to Vishnu'. It denotes a female devotee of Vishnu and is also the name of the Shakti (divine energy) of Vishnu, one of the Sapta Matrikas.
What does Nishka mean?
From the Sanskrit निष्क (niṣka), an ancient gold coin, and by extension a golden necklace or ornament — attested in the Manusmriti and other classical texts. Popular 'pure/honest' glosses on name sites are not supported by the classical sources.