This is the 390th most frequent Icelandic word.
síðastliðinn
"Last" or "past" (referring to something in the recent past).
Here, 'síðastliðinn' refers to the past year, indicating the period of time leading up to now.
Ég hef mikið hugleitt þetta síðastliðna ár.
I have pondered this extensively over the past year.
In this sentence, 'síðastliðinn' describes the previous month, signifying the temporal phase that has just concluded.
Síðastliðinn mánuður var mjög annasamur.
The past month was very busy.
Here, 'síðastliðinn' pertains to the prior week, emphasizing the concluded time span immediately before the present.