This is the 2062nd most frequent German word.
sinken
"Sinken" means "to sink" or "to decline."
In this sentence, 'sinken' is used in a literal sense to describe the physical descent of the ship into water due to damage or another cause.
Das Schiff beginnt zu sinken.
The ship begins to sink.
Here, 'sinken' is utilized in a metaphorical context to describe the lowering or decrease of numerical values, specifically temperatures over time.
Die Temperaturen sinken im Winter stark.
The temperatures decrease significantly in winter.
In this example, 'sinken' metaphorically represents the reduction or decline in an abstract quality, which is the emotional state of courage.