Fling /fliNG/ noun a short period of enjoyment or wild behavior Urban dictionary deliberately short-term sexual relationship between two people. Longer than a one-night stand, not as serious-sounding as "affair", more frankly physical than the discreet or twee "dalliance", the word has the associations of a much needed sexual relief from stress, worry or hangups. No deep personal involvement required, just the sex and a bit of attention.