lucidan

1. sharp; insightful; witty
   To je bila veoma lucidna primedba. — That was a very sharp remark.
   On je lucidan sagovornik i uvek ga je zanimljivo slušati. — He's an insightful person to talk to and always interesting to listen to.
2. (of the mind) lucid; clear-headed
   Baka je i u devedesetoj potpuno lucidna. — Even at ninety, Grandma is completely lucid.
3. (of a dream) lucid
   Nikad nisam imao lucidan san. — I've never had a lucid dream.

In Serbian it most often means "sharp, witty, insightful" about a person, remark or analysis.