The word praṇāyya is irregularly formed when meaning 'disapproved'.,
The word असम्मति is a negative word meaning 'non-agreement'. It means also 'disrespect'.
Thus प्रणाय्यश्चोरः 'the thief is to be disliked'.
Why do we say when meaning 'disapproved'. Because otherwise the regular form is प्र + नी 'to lead' + यत् = प्रणेयः 'tractable'.
The word in the sutra is असम्मति which we have translated as 'disapproved'. But the word सम्मति also means अभिलाष or 'desire'; and असम्मति would therefore, mean 'free from desire or worldly attachment'. Therefore the word असम्मति means also 'free from attachment', as in the following sentence:-
ज्येष्ठाय पुत्राय पिता ब्रह्म प्रभ्रूयात्, प्रणाय्याय अन्तेवासिने नान्यस्मै कस्मैचन 'let the father teach the Secret Doctrine to his eldest son, or to such pupil who is free from worldly attachment, and to no one else'.,