This is the 6687th most frequent Portuguese word.
funda
"Funda" in English means "slingshot" or "sling."
Here, 'funda' refers to a slingshot, an object used for propelling small projectiles.
Ela comprou uma funda para brincar.
She bought a slingshot to play.
In this case, 'funda' is used as a feminine adjective describing something as 'deep' or 'profound'.
A piscina é muito funda.
The pool is very deep.
Again, 'funda' acts as an adjective, relating to the depth characteristic of the cave.