v.1. To sit on the heels with the knees bent forward; squat: My personal trainer hunkered down to help me with the barbells.
2. To take shelter or refuge: The campers hunkered down in the cabin during the blizzard.
3. To hold stubbornly to some position: The candidates hunkered down and refused to admit their mistakes.
4. To apply oneself and start working seriously at something: You need to hunker down and study if you're going to pass that test.