This is the 6791st most frequent Portuguese word.
grossa
"Grossa" in English means "thick" or "coarse."
In this case, 'grossa' is an adjective describing the physical property of the wall, referring to its thickness.
A parede é muito grossa.
The wall is very thick.
Here, 'grossa' is used as an adjective to denote the auditory quality of her voice, indicating it is deep or hoarse.
A voz dela soa grossa por causa da gripe.
Her voice sounds hoarse because of the cold.
In this context, 'grosso' (masculine form of 'grossa') is an adjective meaning 'rude' or 'impolite', used metaphorically to describe the nature of the comment.