Last night, Sammy wrote a riddle! He stayed up all night coming up with this riddle and this is what Jester found under his door this morning.

Dear Jester,

I always find your notes scattered about the castle. Therefore, today I left you one. It is a very difficult puzzle. The following ten words can be divided into two groups of five words. The words within each group will share a common characteristic. What are the two groups? Which words belong in those groups?

dam late lice linger per son stern tent under use

If you don’t have any idea, talk to me. I left a hint.

Sincerly,

Sammy