I thought about it for about 5 minutes before deciding to script it, and got "fobs" and, annoyingly, dismissed "fres" as not a word.
I imagine if I had been more rigorous it wouldn't have taken long to get all the 4 letter ones, since they all have an internal vowel, which was the obvious place to start looking.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.