A case-inflected word denoting a genus (jāti) is compounded with a word denoting praise and the resulting compound is tat-puruṣa ,
The words denoting praise should be rúdhi (रूढि) words like for &c., which retain their specific gender though used along with words of other genders, in apposition with them, as, गोप्रकाण्डम् 'an excellent cow,' अश्वमतल्लिका 'an excellent horse' गोमचर्चिका 'an excellent cow'. These words are generally used at the end of a compound to denote 'excellence' or 'the best of its kind.'
Why do we say 'when denoting genus?' Observe कुमारी मतल्लिका 'an excellent virgin.',