Vishnupurana 3.10.8

3.10.8

tataś ca nāma kurvīta pitaiva daśamehani /
devapūrvaṃ narākhyaṃ hi śarmavarmādisaṃyutam //

"Next, upon the tenth day after birth, let the father give a name to his child; the first term of which shall be the appellation of a god, the second of a man, as Śarman or Varman; the former being the appropriate designation of a Brahman, the latter of a warrior; whilst Gupta and Dása are best fitted for the names of Vaiśyas and Śúdras. A name should not be void of meaning; it should not be indecent, nor absurd, nor ill-omened, nor fearful; it should consist of an even number of syllables; it should not be too long nor too short, nor too full of long vowels; but contain a due proportion of short vowels, and be easily articulated. After this and the succeeding initiatory rites, the purified youth is to acquire religious knowledge, in the mode that has been described, in the dwelling of his spiritual guide.