This is the 15721st most frequent Polish word.
szczupłą
Slim or thin.
The word 'szczupłą' is used as an adjective in accusative case to describe 'sylwetkę' (figure).
Ona ma szczupłą sylwetkę.
She has a slim figure.
Here, 'szczupłą' functions as an adjective in accusative case modifying 'kobietę' (woman), after the verb 'widzę' (I see).
Widzę szczupłą kobietę na zdjęciu.
I see a slim woman in the photo.
In this sentence, 'szczupłą' is an adjective describing 'postacią' (character) in instrumental case for further elaboration.