Iggy Azalea has a big 'ol message to Nick Young and the woman he knocked up -- EFF YOU BOTH!!
Iggy fired off the one finger salute -- which she clarified was directed at Nick and Keonna Green -- while at LAX on Wednesday ... hours after Keonna spilled her guts to US Weekly about her secret affair with the NBA star.
Iggy also claims Keonna's a liar -- saying Keonna is simply not telling the truth about an alleged attempt to contact Iggy to clue her in on the adultery.