Breakdown of Ieri era proprio una giornataccia.
essere
to be
una
a / an (feminine)
ieri
yesterday
proprio
just, exactly (intensifier)
Questions & Answers about Ieri era proprio una giornataccia.
How does the suffix -accia change the meaning of giornata here?
The suffix -accia (and its masculine equivalent -accio) is a pejorative suffix. It adds a negative, bad, or ugly quality to the noun it attaches to. By dropping the final vowel of giornata (day) and adding -accia, it becomes giornataccia (a bad or awful day).
Why use giornata as the base word instead of giorno?
Why is era (imperfect tense) used here instead of è stata (passato prossimo)?
The imperfect tense (l'imperfetto) is used here to describe a state of being or to set a scene in the past. If you said è stata, it would also be correct but would frame the bad day as a single completed event rather than describing the ongoing negative vibe of the day.
I've seen proprio mean 'one's own'. What does it mean in this sentence?
You're right that proprio can be a possessive adjective. However, in this sentence, it acts as an emphasizing adverb meaning 'really', 'truly', or 'exactly'. It intensifies the noun, making it not just a bad day, but a really bad day.