Synonyms:

udasina-vat–as if neutral; asinah–situated; gunaih–by the qualities; yah–one who; na–never; vicalyate–is agitated; gunah–the qualities; vartante–is situated; iti evam–knowing thus; yah–one who; avatisthati–remains; na–never; ingate–flickering.

Translation:

He, who is seated like one unconcerned, being situated beyond these material reactions of the modes of nature, who remains firm, knowing (thus) that the modes alone are active.