Two statements are mutual excusives (and hence, mutually excusive) if they are each given as excuses as to why one can't take part in the other, whilst hiding one's genuine plans.
Sarah: "Sorry Dave, I can't come to the cinema with you later, because I told Louise that we'd have a girls' night in."
Then later,
Sarah: "Sorry Louise, I can't come to girls' night, I promised Dave that I'd go to the cinema with him."
Thus, "going to the cinema with Dave" and "having a girl's night in with Louise" are mutually excusive.
to think of an excuse and the answer to any question which may arise from that excuse.
basically, making sure you're excuse is a full and matching outfit. not an evening dress with a backpack you grabbed at the last minute.
'so you ready for collegetoday?'
'yeah...i've just got to excuserise before Psych hand in'
Fogey/fogy /fougi/ sl. (early 18C+, orig. Scot) old-fashioned, stuck-in-the mud.
Person with old fashioned ideas which he is unwilling to change: Come to the disco and stop being such an old fogey!
You think me an old fogeyand an old tory, his thoughtful voice said. I saw three generations since O’Connel’s time. I remember the famine. Do you know that the orange lodges agitated for repeal of the union twenty years before O’Connel did or before the prelates of your communion denounced him as a demagogue? You fenians forget some things. (James Joyce, Ulysses. Penguin Books,1992. p. 38)