The longest words you can make are 6 letters long.
The others under 6 letters are:
The longest word you can make using those letters once is "keyboard."
counterrevolution contains 17 letters
There is no single-word nine-letter anagram of those letters. The longest words you can make, both of eight letters, are haptenic and whitecap.
The longest word you can make with the letters a, b, c, d, e, f, x, y, and m is "decaf." It is a five-letter word that refers to coffee from which most of the caffeine has been removed. Other combinations yield shorter words, but "decaf" is the most extended valid option using these specific letters.
chromolithographer (18 letters) counterdemonstrator (19 letters)
Decade
The longest word starting with c is counterproductiveness with twentyone letters crystallographically has twenty letters
you are rubbish arent you
There is no anagram. The longest words are bulimia and bulimic (extra C or extra A).
Ace Ice
The missing letters F and C make the word deflects.
You can make the word Scotty out of the letters c o t y t s