olemus
(2a) haagis:
veoki järele haagitav mootorita abiveok

Wiktionary:
3. an unpowered wheeled vehicle, not a caravan or camper, that is towed behind another, and used to carry equipment, etc, that cannot be carried in the leading vehicle
At the end of the day, we put the snowmobiles back on the trailer.

https://en.wikipedia.org/wiki/Trailer_(vehicle)

(2b) treiler:
raskeveohaagis (heavy trailer)
https://duckduckgo.com/?q=%22heavy+trailer%22&t=h_&iax=images&ia=images