Kenyon Martin says "there's no such thing as simple flirting" anymore ... and it's all because men have crossed the line too many times when it comes to picking up women.
The ex-NBA star says he's well aware of the problems many women face in the workplace and other areas in their lives when men come on way too strong ... and it's not right.
"Over the years, men have abused their power," Martin tells TMZ Sports.
So, what happens now? Martin has advice for young men, including NBA players -- "Be smart. Notice the signs."
"No means no! Some resistance? Gotta turn away."
Bottom line ... Kenyon says be respectful to women and you'll be fine.