Flirting, IMO, is stupid in the extreme. I was told that the fact that I have never been on a date in my life is caused by my unwillingness to flirt. Well, then I shall
die without dating, if this is the idiotic junk that precedes dating (blech):
http://en.wikipedia.org/wiki/Flirting
There is a detailed description. I think it is ridiculous and often immoral, but my opinion is irrelevant. You wanted a definition. You got one.