In the chandas (Vedas) the following words are found, which are formed irregularly - niṣṭarkya , devahūya , praṇīya , unnīya , ucchiṣya , marya , staryā , dhvarya , khanya , khānya , devayajyā , āpṛcchya , pratiṣīvya , brahmavādya , bhāvya , stāvya , and pacāyyapṛḍa,
The formation of the above words are extremely irregular and they are all met with in the Vedic literature only. Thus the word निष्टर्क्य is derived from the root कृत् 'to cut', with the preposition निस्, and the affix ण्यत्, instead of क्यप् which is the regular affix, by 110; निः + कृत् + ण्वत् = निः + तृक् + य (the root कृत् transformed into तृक् by transposition) = निष्टर्क्य. As निष्टर्क्ये चिन्वीत् पशुकामः.
The above is apparently a guess-work etymology of grammarians.
So also देवहूय is formed by adding to the root हूयते 'to call' or हू 'to invoke', the affix क्यप् and the upapada देव; the vowel of the root is then lengthened and the augment त (VI. I.71), is not allowed, देव + है or हू + क्यप् = देवहूयः So also प्र + नी (to lead) + क्यप् = प्रणीयः; उत् + नी + क्यप् = उन्नीयः, उत् + शिष् (to leave) + क्यप् = उच्छिष्यम्; मृ (to die) + यत् = मर्यः; स्तृ (to cover) + यत् = स्तर्या; it is always feminine. ध्वृ (to bend) + यत् = ध्वर्यः; खन् (to dig) + यत् = खन्यः; खन् + ण्यत् = खान्यः; देव (God) + यज् (to sacrifice) + यत् = देवयज्या; always used as feminine. आ + पृच्छ् (to ask) + क्यप् = आपृच्छ्यः, प्रति + सीव (to sew) + क्यप् = प्रतिषीव्यः; ब्रह्मण् + वद् (to speak) + ण्यत् = ब्रह्मवाद्यः; भू (to be) + ण्यत् = भाव्यः; स्तु (to praise) + ण्यत् = स्ताव्यः; उप + चि (to collect) + ण्यत् + पृडं = उपचाय्यपृडम्. This last word is formed then only when the word पृड follows: and when the sense is that of 'gold'. When it does not mean 'gold', the form is उपचेयपृडम् ।,