Manava Dharmashastra 2.32

2.32

śarmavad brāhmaṇasya syād rakṣāsamanvitam
vaiśyasya puṣṭisaṃyuktaṃ śūdrasya preṣyasaṃyutam //

(The second part of) a Brahmana's (name) shall be (a word) implying happiness, of a Kshatriya's (a word) implying protection, of a Vaisya's (a term) expressive of thriving, and of a Sudra's (an expression) denoting service.