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hard; solid; tough
stiff; tight; wooden; unpolished (e.g. writing)
strong; firm (not viscous or easily moved)
safe; steady; honest; steadfast
obstinate; stubborn
bookish; formal; stuffy
このパンは硬くて食べにくいです。
This bread is hard and difficult to eat.
机が硬いので、クッションを置きました。
The desk is hard, so I put a cushion on it.
冷蔵庫の肉が硬くなっています。
The meat in the refrigerator has become hard.