A colloquial contraction of かもしれない meaning 'may' or 'might'; indicates possibility or uncertainty. Often used in casual speech, sometimes with a masculine tone.
明日は休みかもしれん。
Tomorrow might be a day off.
彼はもう来ないかもしれんよ。
He might not come anymore, you know.
そんなに簡単には解決できんかもしれん。
It might not be something that can be solved that easily.