The Opening verses of Proverbs

"Proverbs 1:2 To know [give] wisdom and instruction; to perceive the words of understanding; 

3 To receive the instruction of wisdom, justice, and judgment, and equity; 

4 To give subtilty to the simple, to the young man knowledge and discretion. 

“To give subtilty”—acuteness, nicety of distinction, i.e., the ability to distinguish the true from the false, to know the good, and to detect

the bad; to see the right, and to discover any lurking tendency toward wrong. 

“To the simple.”—On this we give the following from Dr. Clarke: The word simple, from simplex, compounded of sine, without, and plica, a fold, signifies properly, plain and honest, one who has no bye-ends in view; who is what he appears to be;...but because honesty and plain dealing are so rare in the world, and none but the truly religious man will practice them, farther than the fear of the law obliges him, hence simple has sunk into a state of progressive deterioration. 

First it signified, as above, without fold, unmixed, uncompounded; this was its radical meaning. 

Secondly, as applied to men, it signified innocent, harmless, without disguise. 

Thirdly, such persons were rather an unfashionable sort of people, it sunk in its meaning to homely, homespun, mean, ordinary. 

And fourthly, as worldly men,...supposed that wisdom, wit, and

understanding, were given to men that they might make the best of them in reference to the things of this life, the word sunk still lower in its meaning, and signified silly, foolish; and there, to the dishonor of our language and morals, it stands….And simplicity, that meant at first openness, plain dealing, downright honesty, is now degraded to weakness, silliness, foolishness.
“To give subtlety to the simple” therefore signifies, to give, acuteness, tact, and nicety of distinction to the honest hearted, the upright, the sincere." 

E.J. Waggoner