On today's Password Plus with Lucille Ball, it was said to be an illegal clue when foxtrot was given for dance. Allen said it was two words, but I just ran it through the spellcheck on my Word, and foxtrot isn't marked wrong. It isn't marked on the spellcheck for this site either.

Maybe "fox trot" was two words at the time, and has more recently been accepted as one word.

If I had my Million Dollar Password board game instruction manual handy I could have the answer. In the game of Password you can use one word but you can't use words that don't fit the clues. Like if the password is "mystery" you could use solve crime case and detective but words like Hitchcock and gumshoe cannot be used as clues. So it's very likely that the word foxtrot was a illegal clue but had it been two words it would've worked as a clue for the password dance
Bestie

I just wanted to add that the comic strip FoxTrot by Bill Amend is titled as one word, with a capital T in the center. It began in 1988.