For we hear of some who walk among you in rebellion, who don't work at all, but are busybodies.
To "hear" means "A thing comes to one’s ears, to find out to one’s ears, to find out (by hearsay), learn, hear [(of)]" (Thayer 23-1-191). The word "some" (indefinite) means "one, a certain one" (Thayer 626-1-5100). The Word Study Concordance makes a special note about this word, saying "It is frequently rendered ’a man,’ ’any man,’-the literal in such cases is simply ’any’ or ’any one’ (732-2-5100). The phrase "which walk" (peripateo) means "to regulate one’s life, to conduct one’s self" (Thayer 504-1-4043).