Left alone, I'm a thing that this riddle has not
By every good writer I shan't be forgot Author's edit: This line has been deemed misleading and unfit for publication. The second line of the riddle titled "Another short riddle" shall henceforth be replaced with the following: It's a thing that is a word that has some letters and definitions.
Rearranged, if you shout this, you might be a liar Author's edit, 2: Well, this is embarrassing. Again, replace with the following: The word described above is an anagram of another word. If shouted, it may have been done so by a liar... or not... You never can tell with that sort of thing.
Again, if shouted, it's a pun used a lot. Author's edit, 3: Apologies, again. I hang my head in shame for such sloppy riddling. Replace with: This word is again an anagram of the two above. It's rather popular as a pun, replacing another word with this.