Synonyms:

yah–one who; tu–but; atma-ratih–takes pleasure; eva–certainly; syat–remains; atma-trptah–self-illuminated; ca–and; manavah–a man; atmani–in himself; eva–only; ca–and; santustah–perfectly satiated; tasya–his; karyam–duty; na–does not; vidyate–exist.

Translation:

One who is, however, taking pleasure in the self, who is illuminated in the self, who rejoices in and is satisfied with the self only, fully satiated–for him there is no duty.