This is the 9059th most frequent Portuguese word.
banana
Banana: A tropical fruit with yellow skin and soft, sweet flesh.
Here 'banana' refers to the fruit, used in its literal sense as an object in the context of shopping.
Comprei uma banana na feira.
I bought a banana at the fair.
In this sentence, 'banana' is used metaphorically to signify a disorganized or chaotic situation.
Minha vida virou uma verdadeira banana depois disso.
My life became a real mess after that.
This usage is literal and refers to the outer cover of the fruit which is commonly associated with being slippery.