This is the 11185th most frequent Portuguese word.
mamão
Papaya.
In this sentence, 'mamão' refers to the fruit commonly known as papaya, used as a food item.
Eu comprei um mamão para o café da manhã.
I bought a papaya for breakfast.
Here, 'mamão' is used colloquially to describe someone or something that is easy or straightforward, like the metaphorical softness of the fruit.
Você sempre facilita as coisas para os outros, é um verdadeiro mamão.
You always make things easy for others; you are a true easy-going person.
In this instance, 'mamão' is metaphorically indicating an action that was straightforward or simple, implying it should have been done more carefully.