Albert Barnes Commentary Job 31:9

"If my heart hath been enticed unto a woman, And I have laid wait at my neighbor`s door;" — Job 31:9 (ASV)

If mine heart have been deceived by a woman - If I have been enticed by her beauty. The word rendered “deceived,” פתה pâthâh, means to open, to expand. It is then applied to that which is open or ingenuous; to that which is unsuspicious (like a youth); and from there is used in the sense of being deceived or enticed (Deuteronomy 11:16; Exodus 22:16; Proverbs 1:10; Proverbs 16:29). The word “woman” here probably means a married woman and stands opposed to “virgin” in verse 1. The crime that he disclaims here is adultery, and he says that his heart had never been allured from conjugal fidelity by the charms or the arts of a woman.

Or if I have laid wait at my neighbor’s door - That is, to watch when he would be absent from home. This was a common practice with those who were guilty of the crime referred to here .