This is the 13305th most frequent Spanish word.
pésima
Extremely bad, awful.
Here, 'pésima' is used as an adjective describing 'actitud', indicating something very negative.
Tu actitud hacia tus compañeros es pésima.
Your attitude towards your peers is lousy.
In this case, 'pésima' modifies 'comida', highlighting a strong disapproval of the quality.
La comida en ese restaurante fue pésima.
The food at that restaurant was terrible.
Here, 'pésima' qualifies 'impresión', signifying a strongly negative opinion.