(not
offensive and
non-sexual term):
a person who outwardly looks unfriendly, but once you get to know them better, they are actually well-intentioned, but shy and clumsy,
friends.
This
definition of a banana stems from the facts that banana peels on the street can make you
slip (the person looks unfriendly) but the
fruit itself is sweet and tasty (the person is shy, clumsy and trying to help others).