b. Of ā́s n. mouth, and úd water, only a case or two are found, in the older language, beside āsán and āsyà, and udán and údaka (432).
399. Some of the alternative stems mentioned above are instances of transition from the consonant to a vowel declension: thus, dánta, mā́sa. A number of other similar cases occur, sporadically in the older language, more commonly in the later. Such are pā́da, -māda, -dāça, bhrājá, viṣṭápa, dvāra and dura, pura, dhura, -dṛça, nā́sā, nidā, kṣípā, kṣapā́, āçā́, and perhaps a few others.
a. A few irregular stems will find a more proper place under the head of Adjectives.
400. Original adjectives having the root-form are comparatively rare even in the oldest language.
a. About a dozen are quotable from the RV., for the most part only in a few scattering cases. But mah, great, is common in RV., though it dies out rapidly later. It makes a derivative feminine stem, mahī́, which continues in use, as meaning earth etc.
401. But compound adjectives, having a root as final member, with the value of a present participle, are abundant in every period of the language.
a. Possessive adjective compounds, also, of the same form, are not very rare: examples are yatásruc with offered bowl; sū́ryatvac sun-skinned; cátuṣpad four-footed; suhā́rd kind-hearted, friendly; rītyàp (i.e. rītí-ap) having streaming waters; sahásradvār furnished with a thousand doors.
b. The inflection of such compounds is like that of the simple root-stems, masculine and feminine being throughout the same, and the neuter varying only in the nom.-acc.-voc. of all numbers. But special neuter forms are of rare occurrence, and masc.-fem. are sometimes used instead.
c. Only rarely is a derivative feminine stem in ī formed: in the older language, only from the compounds with ac or añc (407 ff.), those with han (402), those with pad, as ékapadī, dvipádī, and with dant, as vṛ́ṣadatī, and mahī, ámucī (AV.), úpasadī (? ÇB).
Irregularities of inflection appear in the following:
402. The root han slay, as final of a compound, is inflected somewhat like a derivative noun in an (below, 420 ff.), becoming hā in the nom. sing., and losing its n in the middle cases and its a in the weakest cases (but only optionally in the loc. sing.). Further, when the vowel is lost, h in contact with following n reverts to its original gh. Thus: