寝不足

1. Origins, structure, and basic meaning

• Structure: 寝不足 (ねぶそく) is a nominal expression for insufficient sleep, used predicatively or attributively.
• Basic usage: 寝不足だ predicates the result of staying awake late, while 寝不足のまま modifies an attempt to drive while that condition continues.

2. Common pitfalls and similar expressions

• Predication and continuing state
  • 寝不足だ directly states the current condition, whereas 寝不足のまま shows that the sleep deficit remains unresolved. The latter explains the decision to rest before driving.