To take shelter; to prepare oneself for some eventuality; to focus on a task.(verb)
To stubbornly hold to a position.(verb)
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Use "hunker down" in a sentence
"While officers and engineers anxiously tried to think of a way to counter this new means of warfare, the soldiers manning the defensive ramparts could only hunker down and pray to Rakshinn, or whichever deity they favored, that the terrible new weapon would not be aimed in their direction."