What is the meaning of Proverbs 13:20?

He that walketh with wise [men] shall be wise: but a companion of fools shall be destroyed. (Proverbs 13:20 KJV)

Walk with wise men, and thou shalt be wise; But the companion of fools shall smart for it. (Proverbs 13:20 ASV)

He that walketh with wise [men] becometh wise; but a companion of the foolish will be depraved. (Proverbs 13:20 DBY)

One who walks with wise men grows wise, but a companion of fools suffers harm. (Proverbs 13:20 WEB)

Whoso is walking with wise men is wise, And a companion of fools suffereth evil. (Proverbs 13:20 YLT)

Interlinear

He that walketh <halak> with wise <chakam> men shall be wise: <chakam> but a companion <ra`ah> of fools <k@ciyl> shall be destroyed. <ruwa`> (Proverbs 13:20 KJV)

Matthew Henry’s Commentary

Note:  

1. Those that would be good must keep good company, which is an evidence for them that they would be good (men’s character is known by the company they choose) and will be a means of making them good, of showing them the way and of quickening and encouraging them in it. He that would be himself wise must walk with those that are so, must choose such for his intimate acquaintance, and converse with them accordingly; must ask and receive instruction from them, and keep up pious and profitable talk with them.  Miss not the discourse of the elders, for they also learned of their fathers, Ec 8:9. And (Ec 6:12), Be willing to hear every godly discourse, and let not the parables of understanding escape thee.  

2. Multitudes are brought to ruin by bad company: A companion of fools shall be broken (so some), shall be known (so the LXX), known to be a fool; noscitur ex socio–he is known by his company. He will be like them (so some), will be made wicked (so others); it comes all to one, for all those, and those only, that make themselves wicked, will be destroyed, and those that associate with evil-doers are debauched, and so undone, and at last ascribe their death to it.  

Extract from Proverbs Appendix. See MHC for Pr 31:31  

29. Of good and bad company, Pr 13:20; Pr 14:7; Pr 28:7; Pr 29:3.