To tell someone to 'fick off' is essentially telling them to 'fuck off' albeit you typed it wrong because of old age.
Similar in principle to spelling 'Team' with a 'Y', then attempting to pass it off as the Liberian spelling of the word.
Andrea gave Susie a leaflet for the weekly senior citizens aerobics class at the Leisure Centre on Wednesday mornings. For some time Susie had assumed Andrea was being friendly. She was not a senior citizen, she definitely did not mutter 'fick-off' under her breath as she walked off in her leopard skinbra.
German expression meaning "fuck off" or just "fuck you", literally "fuck your knee". The origin of this expression is a pun with the archaic word "Kniefiez", meaning a very avaricious person such as Scrooge McDuck. Therefore, its original meaning was "If you're to cheap for that, you can go and fuck yourself.". However, with time it has become a more general expression that could be used equally well in any other context.
100 Mark für einmal kurz blasen? Fick dich ins Knie!