This is the 228th most frequent Indonesian word.
semakin
"Semakin" means "increasingly" or "the more."
In this sentence, 'semakin' is used to indicate a growing or increasing intensity or degree of coldness over time.
Udara di puncak gunung semakin dingin saat malam hari tiba.
The air at the mountain peak becomes increasingly cold as night falls.
In this instance, 'semakin' describes the progressive increase in the density of the streets as time progresses.
Jalanan kota semakin padat menjelang akhir pekan.
The city streets become more crowded as the weekend approaches.
Here, 'semakin' connects two clauses to demonstrate a proportional relationship: as one factor increases, the other also changes accordingly.