Respected Scholars,

Presently I am engaged studying "NaishkarmaSiddhi" by Sureshwaracharya.
I would be grateful if someone may enlighten me on the actual connotation of the term "Naishkarma". I feel curious to get an answer to this , in the light of the fact that the book contains sutras which specifies the idea that observing/ performing daily/regular duties(NityaKarma), helps us to attain "Moksha" or liberation.
Then why is the title of book"NaishkarmaSiddhi"?
Regards
Alakendu Das