For those who do not know the word ( F ) comes from the British Army , when troops went overseas and officers at home courted other departed officers wives at home and were caught in the act of it . it was put into service records as ( For ) Understanding ( Carnel ) Knowledge and was a black mark on his record and denotes he was no gentleman , in the eyes of the crown anyway , look this up guys its true .
The other one is the flipping of the bird which is also English , due to the battle of Agincourt in I believe the yr. 1041 when the French wanted to cut off the bow shooting fingers of King Henrys Archers so in defence of themselves they ( flipped of the French troops ) and this is the same battle of ( We few we happy few )