Those adverbially used accusatives of secondary adjective compounds which have an indeclinable or particle as prior member are reckoned by the Hindu grammarians as a separate class of compounds, and called by the name avyayībhāva.

a. This term is a derivative from the compound verb (1094) made up of avyaya uninflected and √bhū, and means conversion to an indeclinable.

b. The prepositional compounds (1310) are especially frequent in this use: thus, for example, anuṣvadhám by one's own will, abhipūrvám and parovarám in succession, ādvādaçám up to twelve, pratidoṣám at evening, samakṣám in sight. Instances given by the grammarians are: adhihari upon Hari, uparājam with the king, upanadam or upanadi near the river,pratyagni toward the fire, pratiniçam every night, nirmakṣikam with freedom from flies.

c. A large and important class is made up of words having a relative adverb, especially yathā, as prior member. Thus, for example, yathāvaçám as one chooses (váça will), yathākṛtámas done [before], according to usage, yathānāmá by name, yathābhāgám according to several portion, yathān̄gám and yathāparú limb by limb, yatrakā́mam whither one will,yāvanmātrám in some measure, yāvajjīvám as long as one lives, yāvatsábandhu according to the number of relations.

d. These compounds are not common in the old language; RV. has with yathā only four of them, AV. only ten; and no such compound is used adjectively except yācchreṣṭha RV.,yāvacchreṣṭhá AV. as good as possible. ÇB. has yathākārín, yathācārín, yáthākāma, yáthākratu as adjectives (followed in each case by a correlative táthā). The adjective use in the later language also is quite rare as compared with the adverbial.

e. Other cases than the accusative occasionally occur: thus, instrumental, as yathāsaṁkhyena, yathāçaktyā, yathepsayā, yathāpratiguṇāis; and ablative, asyathāucityāt.

f. A class of adverbs of frequent occurrence is made with sa: e. g. sakopam angrily, sādaram respectfully, sasmitam with a smile, saviçeṣam especially.