Finnish and Estonian are close but not mutually intelligible.
I found this really funny answer on English language Quora that covers dozens of false friends (= words whose meaning you might think you have guessed but really haven't).
https://www.quora.com/Are-Estonian-and-Finnish-as-mutually-intelligible-as-Spanish-and-Portuguese
Check out the answer written by Piret Kivi (she's Estonian who apparently knows Finnish pretty well).
A sample:
If in Estonian you are ruumis 13 then you are in room 13. In Finnish you would be body number 13 or dead body number 13. In Estonian you would maybe say koristan this dead body because koristan means I clean or tidy up. In Finnish it would mean I decorate the dead body.
After all this mess you decide in Estonian to go linna pappi raiskama, i.e. to go to the city to spend money. Except that in Finnish people who go linnaan pappia raiskaamaan would go to prison because they went to a castle to rape a priest and also because they went to a prison to rape a priest.