This is the 759th most frequent Spanish word.
física
"Física" means "physics" or "physical" (related to the body).
In this sentence, 'física' is used as an adjective to describe the word 'condición' (condition), referring to the physical state of the body.
Ella tiene una condición física excepcional.
She has an exceptional physical condition.
Here, 'físico' (masculine form due to matching with 'bienestar') is used as an adjective, qualifying 'bienestar' (well-being), to specify it concerns the physical aspect.
Estoy interesado en mejorar mi bienestar físico mediante el ejercicio.
I am interested in improving my physical well-being through exercise.
Here, the word 'física' is used as a noun to refer to the natural science of physics, which studies matter, its motion, and its behavior through space and time.