What does Proverbs 2:16 mean?

This verse uses the metaphor of a strange woman. It's interesting to think of sin in this way, as a "forbidden" stranger. In truth, we were not created to sin, we were created to reflect God's image and His righteousness (Genesis 1:26). When sin entered the world through Adam it corrupted our nature and caused a rift between man and God.

Solomon himself was a man who took advantage of every luxury available to a man. He knew, first hand, what it was to sin and sin excessively, as shown in the book of Ecclesiastes. So, when Solomon gives this warning it should be one we pay that much more attention to. The adulteress of sin flatters us with her words. Sin looks enticing, and for a brief moment it is even enjoyable. Yet by falling into sin we commit "adultery" against our Creator. Our relationship with Christ is compared to that of a marriage (Revelation 19:7–8), and sexual sin is especially grievous (1 Corinthians 6:18).

Combining these ideas, this verse tells us that sin is not what we were created for, it is a stranger, yet it is as alluring as an adulteress. We would do well to flee from it.