Google says the longest cited Finnish word is "lentokonesuihkuturbiinimoottoriapumekaanikkoaliupseerioppilas," meaning "airplane jet turbine engine auxiliary mechanic non-commissioned officer student." Can you make one longer?
I'm guessing this means official titles, names or otherwise somehow constricted words.
I can easily extend it by adding few words: "Antiikkilentokonesuihkuturbiinimoottoriapumekaanikkoaliupseerioppilasehdokas" meaning "antique airplane jet turbine engine auxiliary mechanic non-commissioned officer student candidate".