This is the 3861st most frequent Portuguese word.
delgada
Slim; thin; slender.
Here 'delgada' is used as an adjective describing someone's physical appearance, meaning slender or slim.
Ela tem uma figura delgada e elegante.
She has a slender and elegant figure.
In this sentence, 'delgada' is metaphorically describing the thinness of the distinction between two concepts.
A linha delgada entre o sucesso e o fracasso pode ser difícil de identificar.
The thin line between success and failure can be hard to identify.
Here 'delgada' is used to describe the thinness of an object in a tactile manner.